Talk:Dog Development

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Cite this page: Hill, M.A. (2021, October 21) Embryology Dog Development. Retrieved from

The Genetics of the Dog

Edited by A Ruvinsky, Professor of Genetics, University of New England, Australia, J Sampson, The Kennel Club, London, UK

October 2001 / Hardback / 576 Pages / 9780851995205


Martin. EW. Development of the vascular system in five to twenty-one somite dog embryos. (1958). MSc. Thesis, Department of Zoology, Kansas State College of Agriculture.


Computed tomographic evaluation of cleft palate in one-day-old puppies

BMC Vet Res. 2018 Oct 20;14(1):316. doi: 10.1186/s12917-018-1642-6.

Pankowski F1, Paśko S2, Max A3, Szal B1, Dzierzęcka M1, Gruszczyńska J4, Szaro P5, Gołębiowski M5, Bartyzel BJ6.

Abstract BACKGROUND: Cleft palate is a birth defect characterized by a lack of fusion between structures forming the palate. Causes include a multitude of factors, both genetic and environmental. Computed tomography (CT) is widely used to evaluate morphological features and diagnose head disorders in adult dogs. However, there is less data about its use in neonatal dogs. The purpose of this study was to perform CT evaluation of palatal defects in one-day-old puppies and to present a novel approach of 3D modeling in terms of cleft palate assessment.

RESULTS: Macroscopic and CT examinations were performed in 23 stillborn or euthanized purebred newborn puppies. On the basis of CT data, a 3D model was prepared and the cleft surface area was then calculated. A multi-stage approach, which utilised software such as 3D Slicer and Blender, was applied. Palatal defects were found in ten dogs, of which five had cleft palate, three had bilateral cleft lip and palate, one had a unilateral cleft lip and palate and one had a unilateral cleft lip. The surface area of the clefts ranged from 31 to 213 mm2, which made up respectfully 11 to 63% of the total surface area of the palate. No abnormalities were found in thirteen dogs and they made up the control group.

CONCLUSIONS: Computed tomography and 3D modeling were very effective in evaluation of palatal disorders in newborn dogs. 3D models adapted to the natural curvature of the palate were created and more precise data was obtained. Morphological characteristics, CT findings and advanced image analysis of cleft palate in neonates obtained from these models increase the knowledge about this malformation in dogs.

KEYWORDS: 3D modeling; Anatomy; Dogs; Newborn; Radiology; STL PMID: 30342508 PMCID: PMC6195986 DOI: 10.1186/s12917-018-1642-6

Contrast-enhanced ultrasonography of maternal and fetal blood flows in pregnant bitches

Theriogenology. 2018 Oct 30;125:129-134. doi: 10.1016/j.theriogenology.2018.10.027. [Epub ahead of print]

Orlandi R1, Vallesi E2, Boiti C2, Polisca A3, Troisi A3, Righi C4, Bargellini P2. Author information Abstract We evaluated the potential usefulness of CEUS to assess fetal-maternal circulation during pregnancy in dogs. Nine bitches were examined at 23, 30, and 45 days of gestation using an ultrasound machine (LOGIQ E9) and SonoVue® contrast media as echo-signal enhancer. Qualitative and quantitative evaluation of contrast enhancement patterns of uterine artery and utero/placental vessels were performed on recorded images. Independently of the gestational periods, the qualitative evaluation showed the initial wash-in phase from the first appearance of the uterine artery to the rapid distribution in embryonic vesicles or placenta to the progressive washout, whilst there was no enhancement of either embryos or fetuses in any bitch. Independent of gestational age, parameters derived from quantitative analysis of time intensity-curves of contrast enhancement (peak intensity, time to peak, rise time, washout) did not vary between proximal placenta, distal placenta, and uterine artery. With the progression of gestation, AUC values did not change in both proximal and distal placenta, but in the uterine artery it was lower (P ≤ 0.05) at day 30 than at day 23 (464.8 ± 16.1 vs.596.4 ± 28.1, respectively). In conclusion, CEUS appears to safely permit evaluation of the maternal and fetal vessels in the first two third of gestation, without any clinically relevant adverse effects. Further studies in a larger number of bitches in different stages of pregnancy are needed to establish standard parameters for normal pregnancies that can be used to detect abnormalities of pregnancy. KEYWORDS: Bitch; Contrast agent; Pregnancy PMID: 30414566 DOI: 10.1016/j.theriogenology.2018.10.027


Dog and mouse: toward a balanced view of the mammalian olfactory system

Front Neuroanat. 2014 Sep 25;8:106. doi: 10.3389/fnana.2014.00106. eCollection 2014.

Barrios AW, Sánchez-Quinteiro P, Salazar I.


Although the most intensively studied mammalian olfactory system is that of the mouse, in which olfactory chemical cues of one kind or another are detected in four different nasal areas [the main olfactory epithelium (MOE), the septal organ (SO), Grüneberg's ganglion, and the sensory epithelium of the vomeronasal organ (VNO)], the extraordinarily sensitive olfactory system of the dog is also an important model that is increasingly used, for example in genomic studies of species evolution. Here we describe the topography and extent of the main olfactory and vomeronasal sensory epithelia of the dog, and we report finding no structures equivalent to the Grüneberg ganglion and SO of the mouse. Since we examined adults, newborns, and fetuses we conclude that these latter structures are absent in dogs, possibly as the result of regression or involution. The absence of a vomeronasal component based on VR2 receptors suggests that the VNO may be undergoing a similar involutionary process. KEYWORDS: dog; evolution; morphology; olfactory epithelium; olfactory subsystems

PMID 25309347

Expression of genes involved in the embryo-maternal interaction in the early pregnant canine uterus

Reproduction. 2014 Jan 30. [Epub ahead of print]

Kautz E, Gram A, Aslan S, Ay SS, Selcuk M, Kanca H, Koldas E, Akal E, Karakas K, Findik M, Boos A, Kowalewski MP. Author information


Although there is no acute luteolytic mechanism in the absence of pregnancy in the bitch a precise and well-timed embryo-maternal interaction seems to be required for the initiation and maintenance of gestation. Since only limited information is available about these processes in dogs, here, the uterine expression of possible decidualization markers was investigated during the pre-implantation stage (days 10-12) of pregnancy and in corresponding non-pregnant controls. Additionally, the expression of selected genes associated with blastocyst development and/or implantation was investigated in embryos flushed from the uteri used for this study (unhatched and hatched blastocysts). There was an upregulated expression of prolactin receptor (PRLr) and insulin-like growth factor 2 (IGF2) observed pre-implantation. The expression of PRL and of IGF1 was unaffected, and neither was the expression of progesterone- or estrogen receptor β (ERβ). In contrast, ERα-levels were elevated during early pregnancy. Prostaglandin (PG)-system revealed upregulated expression of PGE2-synthase and its receptors, EP2 (PTGER2) and EP4 (PTGER4), and of the PG-transporter. Elevated levels of PGF2α-synthase (PGFS/AKR1C3) mRNA, but not the protein itself, were noted. Expression of prostaglandin-endoperoxide synthase 2 (PTGS2,COX2) remained unaffected. Most of the transcripts were predominantly localized to the uterine epithelial cells, myometrium and, to a lesser extent, to the uterine stroma. PGES mRNA was abundantly expressed in both groups of embryos and appeared higher in the hatched ones. The expression level of IGF2 mRNA appeared higher than that of IGF1 mRNA in hatched embryos. In unhatched embryos IGF1, IGF2 and COX2 mRNA levels were below the detection limit.

PMID 24481956


Similar patterns of embryo development in canine oocytes cultured in vitro at oxygen tensions of 5 and 20%

Theriogenology. 2013 Apr 5. pii: S0093-691X(13)00075-7. doi: 10.1016/j.theriogenology.2013.02.022. [Epub ahead of print]

Rodrigues BA, Rodrigues CA, Salviano MB, Willhelm BR, Collares FJ, Rodrigues JL. Source Laboratory of Embryology and Biotechniques of Reproduction, Faculty of Veterinary Medicine, UFRGS, Porto Alegre, Rio Grande do Sul, Brazil. Electronic address: Abstract The influence of two oxygen tensions (5 and 20%) on fertilization, cleavage, development, and morphological quality of canine embryos produced in vitro was investigated. To assess embryo production, canine oocytes (N = 608) were matured in vitro at 20% oxygen tension in TCM 199 supplemented with glucose (11 mM) and 0.1% polyvinyl alcohol. Oocytes and sperm were coincubated at 37 °C for 24 hours in serum-free medium. Subsequently, presumptive zygotes were cultured in vitro in synthetic oviductal fluid in either 5% CO2 in air (20% oxygen; N = 298) or 5% O2, 5% CO2 and 90% N2 (5% oxygen; N = 310) for 7 days. Regardless of the oxygen concentration (5 vs. 20%), rates of pronucleus formation, cleavage, and embryo development up to the eight-cell stage did not differ (46/310 [14.8%] vs. 35/298 [11.7%], respectively; P > 0.05). Moreover, similar proportions of embryos developed in 20 and 5% oxygen tensions (18/298 vs. 27/310). The oocyte nuclear maturation (metaphase II), in terms of decondensed sperm heads, pronucleus formation, cleavage, and embryo development, was similar (P = 0.299) between the atmospheric (20% O2; 12.4% [37/298]) and reduced oxygen tensions (5% O2; 15.8% [49/310]) at all steps of the in vitro culture (IVC) after in vitro fertilization (IVF). To our knowledge, this was the first study that demonstrated that canine embryos can be produced using a low-oxygen in vitro culture system. Both oxygen tensions (5 and 20%) resulted in similar embryonic development and therefore were feasible for IVC of canine oocytes. Copyright © 2013 Elsevier Inc. All rights reserved.

PMID 23566669

Domestic Carnivore's Development: Detection of Oct-4, A Pluripotency Marker, in Pharyngeal Arches

Reprod Domest Anim. 2013 Feb 5. doi: 10.1111/rda.12147. [Epub ahead of print]

Roballo K, Ercolin A, Casals J, Pieri N, Barreto R, Illera M, Martins D, Miglino M, Ambrósio C. Source Department of Veterinary Medicine, Faculty of Animal Sciences and Food Engineering, University of São Paulo, Pirassununga, SP, Brazil. Abstract Very few carnivore's embryology is reported mainly restricted to old literature without new technique analyses. Also, their development focuses on pharyngeal arches and stem cell sources and the high capacity for differentiation from those cells to generate embryonic tissue. We aimed to use immunohistochemistry to prove the potentiality of these stem cell niches. The results were to highlight the timetable for the development of dogs and cats, the proper formation of pharyngeal arches and the description of these cells on first and second arches since 17-25 days of pregnancy. After that, the differentiation process is reduced. © 2013 Blackwell Verlag GmbH.

PMID 23379423


Stage of development Days after fertilisation Cells/Stage

Two cell 1-2 2 Eight cell 2.5-3 8 Genome activation 2.5-3 8 Morula compaction 4-5 ~16 Blastocyst formation ~6 32-64 Entry into the uterus 7-8 ~64+ Free migration between uterine horns 8-10 ~1 mm Hatching from zona pellucida ~12 2-3 mm Implantation begins 14-15 -//- Primitive streak (gastrulation begins) 15-16 ~4 mm First somite pair ~16 ~4-6 mm Notochord 16-17 somites Neural groove 17-18 Head fold ~19 Closing of neural tube 19-20 Vascularised yolk sac 20-21 Heart beats 20-22 (22-23) Visible limb buds 24-25 vertebrae - Optic and otic vesicles visible 25-26 Well developed tail and elongating limbs 31-33 Testicular differentiation begins 35-36 growing fetus Pituitary gland developed 38 Eyelids close, lids fused, claws on digits 40 Ossification recognizable ~42 Mammae begin to grow ~42 Hair coat developed 55 Birth 62-64 (considerable variation)


A Digital Atlas of the Dog Brain

Datta R, Lee J, Duda J, Avants BB, Vite CH, Tseng B, Gee JC, Aguirre GD, Aguirre GK. Source Department of Neurology, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.


There is a long history and a growing interest in the canine as a subject of study in neuroscience research and in translational neurology. In the last few years, anatomical and functional magnetic resonance imaging (MRI) studies of awake and anesthetized dogs have been reported. Such efforts can be enhanced by a population atlas of canine brain anatomy to implement group analyses. Here we present a canine brain atlas derived as the diffeomorphic average of a population of fifteen mesaticephalic dogs. The atlas includes: 1) A brain template derived from in-vivo, T1-weighted imaging at 1 mm isotropic resolution at 3 Tesla (with and without the soft tissues of the head); 2) A co-registered, high-resolution (0.33 mm isotropic) template created from imaging of ex-vivo brains at 7 Tesla; 3) A surface representation of the gray matter/white matter boundary of the high-resolution atlas (including labeling of gyral and sulcal features). The properties of the atlas are considered in relation to historical nomenclature and the evolutionary taxonomy of the Canini tribe. The atlas is available for download (

Citation: Datta R, Lee J, Duda J, Avants BB, Vite CH, et al. (2012) A Digital Atlas of the Dog Brain. PLoS ONE 7(12): e52140. doi:10.1371/journal.pone.0052140

Editor: George Paxinos, The University of New South Wales, Australia

Received: August 20, 2012; Accepted: November 8, 2012; Published: December 20, 2012

Copyright: © 2012 Datta et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PMID 23284904

Inherited liver shunts in dogs elucidate pathways regulating embryonic development and clinical disorders of the portal vein

Mamm Genome. 2012 Feb;23(1-2):76-84. Epub 2011 Nov 4.

van Steenbeek FG, van den Bossche L, Leegwater PA, Rothuizen J. Source Faculty of Veterinary Medicine, Utrecht University, Yalelaan 104, PO Box 80154, 3508 TD Utrecht, The Netherlands.


Congenital disorders of the hepatic portal vasculature are rare in man but occur frequently in certain dog breeds. In dogs, there are two main subtypes: intrahepatic portosystemic shunts, which are considered to stem from defective closure of the embryonic ductus venosus, and extrahepatic shunts, which connect the splanchnic vascular system with the vena cava or vena azygos. Both subtypes result in nearly complete bypass of the liver by the portal blood flow. In both subtypes the development of the smaller branches of the portal vein tree in the liver is impaired and terminal branches delivering portal blood to the liver lobules are often lacking. The clinical signs are due to poor liver growth, development, and function. Patency of the ductus venosus seems to be a digenic trait in Irish wolfhounds, whereas Cairn terriers with extrahepatic portosystemic shunts display a more complex inheritance. The genes involved in these disorders cannot be identified with the sporadic human cases, but in dogs, the genome-wide study of the extrahepatic form is at an advanced stage. The canine disease may lead to the identification of novel genes and pathways cooperating in growth and development of the hepatic portal vein tree. The same pathways likely regulate the development of the vascular system of regenerating livers during liver diseases such as hepatitis and cirrhosis. Therefore, the identification of these molecular pathways may provide a basis for future proregenerative intervention.

PMID 22052005

Development and characterization of 5 canine B-cell lymphoma cell lines

Leuk Res. 2012 May;36(5):601-6. Epub 2011 Dec 1.

Zwingenberger AL, Vernau W, Shi C, Yan W, Chen X, Gordon IK, Kent MS. Source Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.


Canine and human lymphoma share similar characteristics in disease development and response to therapy. Translational research can be furthered using tools such as canine cell lines to model therapeutic compounds and strategies. We developed 5 B-cell lymphoma cell lines from dogs with confirmed large B-cell lymphoma. These cell lines were CD3, CD18, CD20, and CD90 positive with variable CD79a, CD1c and CD34 expression. All cell lines were tumorigenic in Nu/nu mice and were wild type for p53. Canine lymphoma cell lines serve as an important resource for translational lymphoma research. Copyright © 2011 Elsevier Ltd. All rights reserved.

PMID 22136758


69 differential and quantitative analysis of dog oviductal fluid

Reprod Fertil Dev. 2011 Dec;24(1):147.

Reynaud K, Labas V, Harichaux G, Thoumire S, Tahir MZ, Chastant-Maillard S, Saint-Dizier M. Source INRA- ENVA BDR, Maisons-Alfort, France;


The major reproductive peculiarity of the bitch is that ovulation releases prophase I (germinal vesicle, GV, immature) oocytes. Resumption of meiotic maturation, as well as fertilisation and embryonic development to the morula stage occur in the oviduct. Because the dog is a biomedical model for human diseases and also a model for endangered canid species, the development of assisted reproduction techniques would be of great interest. To date, in vitro-produced canine embryos remain exceptional and no puppy has been born. The main limiting factors of in vitro embryo production are the low oocyte maturation rates, the poor oocyte quality and the high polyspermy. A better knowledge of the composition of oviductal fluid during the periovulatory period may help to mimic the in vivo conditions for in vitro oocyte culture and, thereafter, their fertilisation and embryonic development. The objective of this study was to analyse the oviductal fluid by a label-free quantitative proteomic workflow based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) protein separation, nano-scale liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analysis and quantitative method using spectral counting. Ovarian cycles were followed by vaginal smears, ultrasonography and progesterone blood assays. Oviductal fluids were collected from 3 beagle bitches, after ovariectomies performed 3.5 days after ovulation. After dissection, the ampulla and isthmus were separated and flushed with 50μL of PBS. Oviductal fluids were submitted to 1D SDS-PAGE and all bands were digested with trypsin. Peptide extracts were analysed on an Ettan multidimensional LC (MDLC) system coupled to a linear ion trap quadrupole (LTQ) mass spectrometer. After protein identification using Mascot server and with Swiss-Prot and National Center for Biotechnology Information (NCBI) databases, bioinformatic processing of data and statistic analysis (t-test with P<0.05) were performed using the spectral counting quantitative module of the Scaffold software. Using this strategy, 427 proteins were qualitatively identified in canine oviductal fluid. Three proteins were specific of the ampulla, 10 specific of the isthmus and 414 were found in both oviductal parts. Among these common proteins, some were differentially expressed, from 1.25 to 9 times higher (HV303_Human, RLA2_Horse, SPRL1_Human, SODC_CANFA, PROF1_Human, ARF4_Bovin and TRXR1_Bovin). The gene ontology analysis displayed biological pathways specific to the biology of reproduction (6 proteins; RUVB1_Human, OVGP1_Pig, STAT3_Human, PLAK_Human, GPX3_Rat and DYL1_Human). These candidate proteins and especially oviduct-specific glycoprotein and glutathione peroxidase, will now be validated by immunodetection methods.

PMID 22394791

Early development and putative primordial germ cells characterization in dogs

Reprod Domest Anim. 2011 Feb;46(1):e62-6. doi: 10.1111/j.1439-0531.2010.01631.x.

Martins DS, Ambrósio CE, Saraiva NZ, Wenceslau CV, Morini AC, Kerkis I, Garcia JM, Miglino MA. Source Faculty of Animal Science and Food Engineering, University of Sao Paulo, Pirassununga, São Paulo, Brazil.


Previously, three distinct populations of putative primordial germ cells (PGCs), namely gonocytes, intermediate cells and pre-spermatogonia, have been described in the human foetal testis. According to our knowledge, these PGCs have not been studied in any other species. The aim of our study was to identify similar PGC populations in canine embryos. First, we develop a protocol for canine embryo isolation. Following our protocol, 15 canine embryos at 21-25 days of pregnancy were isolated by ovaryhysterectomy surgery. Our data indicate that dramatic changes occur in canine embryo development and PGCs specification between 21 to 25 days of gestation. At that moment, only two PGC populations with distinct morphology can be identified by histological analyses. Cell population 1 presented round nuclei with prominent nucleolus and a high nuclear to cytoplasm ratio, showing gonocyte morphology. Cell population 2 was often localized at the periphery of the testicular cords and presented typical features of PGC. Both germ cell populations were positively immunostained with anti-human OCT-4 antibody. However, at day 25, all cells of population 1 reacted positively with OCT-4, whereas in population 2, fewer cells were positive for this marker. These two PGCs populations present morphological features similar to gonocytes and intermediate cells from human foetal testis. It is expected that a population of pre-spermatogonia would be observed at later stages of canine foetus development. We also showed that anti-human OCT-4 antibody can be useful to identify canine PGC in vivo. © 2010 Blackwell Verlag GmbH.

PMID 20477984

A canine model of Cohen syndrome: Trapped Neutrophil Syndrome

BMC Genomics. 2011 May 23;12:258. doi: 10.1186/1471-2164-12-258.

Shearman JR, Wilton AN. Source School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.


BACKGROUND: Trapped Neutrophil Syndrome (TNS) is a common autosomal recessive neutropenia in Border collie dogs.

RESULTS: We used a candidate gene approach and linkage analysis to show that the causative gene for TNS is VPS13B. We chose VPS13B as a candidate because of similarities in clinical signs between TNS and Cohen syndrome, in human, such as neutropenia and a typical facial dysmorphism. Linkage analysis using microsatellites close to VPS13B showed positive linkage of the region to TNS. We sequenced each of the 63 exons of VPS13B in affected and control dogs and found that the causative mutation in Border collies is a 4 bp deletion in exon 19 of the largest transcript that results in premature truncation of the protein. Cohen syndrome patients present with mental retardation in 99% of cases, but learning disabilities featured in less than half of TNS affected dogs. It has been implied that loss of the alternate transcript of VPS13B in the human brain utilising an alternate exon, 28, may cause mental retardation. Mice cannot be used to test this hypothesis as they do not express the alternate exon. We show that dogs do express alternate transcripts in the brain utilising an alternate exon homologous to human exon 28.

CONCLUSION: Dogs can be used as a model organism to explore the function of the alternately spliced transcript of VPS13B in the brain. TNS in Border collies is the first animal model for Cohen syndrome and can be used to study the disease aetiology.

PMID 21605373

Bilateral ectrodactyly and spinal deformation in a mixed-breed dog

Can Vet J. 2011 Jan;52(1):47-9.

Carvallo FR, Domínguez AS, Morales PC. Source Escuela de Medicina Veterinaria, Universidad Santo Tomás, Talca, 255 Carlos Schorr Av., Talca, Chile. Abstract A 3-year-old, female mixed-breed dog had malformations of both thoracic limbs and the vertebral column. Radiographs of the forelimbs showed bilateral development of 2 digits and aplasia of 3 carpal bones. Kyphosis, scoliosis, and deformed vertebrae were present in the thoracolumbar vertebral column.

PMID 21461206


Total neuron numbers in CA1-4 sectors of the dog hippocampus

Indian J Med Res. 2010 Jun;131:780-5.

Rağbetli MC, Aydinlioğlu A, Koyun N, Yayici R, Arslan K. Source Departments of Histology & Embryology , Medical Faculty, Yüzüncü Yil University,Van, Turkey.


BACKGROUND & OBJECTIVES: Early reports addressed morphological asymmetry in the cross-sectional width of the rat hippocampus. The present study was aimed at counting total number of neurons in CA1-4 sectors and the subiculum of the dog hippocampus as well as investigating possible left /right and male/female asymmetry.

METHODS: Adult mongrel dogs (8 female and 5 male) were assessed by the right and left pawedness and sacrificed by exsanguinations. In each hippocampus dissected, the total neuron numbers of CAs and subiculum were estimated by the physical fractioning method.

RESULTS: Significant hemispheric asymmetries were found in the number of pyramidal cells of CA1, CA3/2, CA4 and the subiculum. Sex difference was also found in the subiculum, in favour of the males.

INTERPRETATION & CONCLUSION: Our study indicated a left dominant asymmetry in males and right dominancy in females as well as no functional asymmetry in specific regions of the dog hippocampus. Further investigations are necessary to verify the hypothesis that hippocampal morphological asymmetries in normal subjects are functionally related in memory or in cognitive skills.

PMID 20571166

Embryo biotechnology in the dog: a review

Reprod Fertil Dev. 2010;22(7):1049-56.

Chastant-Maillard S, Chebrout M, Thoumire S, Saint-Dizier M, Chodkiewicz M, Reynaud K.

Department of Reproduction, Ecole Nationale Vétérinaire d'Alfort, 94700 Maisons-Alfort, France. Abstract Canine embryos are a scarce biological material because of difficulties in collecting in vivo-produced embryos and the inability, to date, to produce canine embryos in vitro. The procedure for the transfer of in vivo-produced embryos has not been developed adequately, with only six attempts reported in the literature that have resulted in the birth of 45 puppies. In vitro, the fertilisation rate is particularly low ( approximately 10%) and the incidence of polyspermy particularly high. So far, no puppy has been obtained from an in vitro-produced embryo. In contrast, cloning of somatic cells has been used successfully over the past 4 years, with the birth of 41 puppies reported in the literature, a yield that is comparable to that for other mammalian species. Over the same period, canine embryonic stem sells and transgenic cloned dogs have been obtained. Thus, the latest reproductive technologies are further advanced than in vitro embryo production. The lack of fundamental studies on the specific features of reproductive physiology and developmental biology in the canine is regrettable in view of the increasing role of dogs in our society and of the current demand for new biological models in biomedical technology.

PMID 20797342

Tumour Necrosis Factor in the Canine Endometrium: An Immunohistochemical Study

Reprod Domest Anim. 2010 Sep 29. doi: 10.1111/j.1439-0531.2010.01681.x.

Payan-Carreira R, Pires M, Ström Holst B, Rodriguez-Martinez H.

CECAV, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal SLU, Department of Clinical Sciences, Uppsala Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden. Abstract Tumour necrosis factor (TNF), a pleiotropic cytokine that regulates cell growth and differentiation as well as the synthesis of other cytokines, has been identified in the uterus of several species describing a cyclic pattern, eventually under ovarian steroid regulation. Information is yet limited on the presence of TNF protein in the canine endometrium during the oestrous cycle and early pregnancy. This study depicts the temporal immunolocalization of TNF in the bitch endometrium along the oestrous cycle and changes associated with the early steps of embryo invasion. TNF immunolabelling was found in both the stromal fibroblasts and epithelial components of the canine endometrium in all stages studied. Stromal immunostaining was more intense than that of the epithelia, in all the stages of the oestrous cycle. In addition, a tendency for a decrease in the surface epithelium intensity score was found in early dioestrus. A positive glandular content was only observed in anoestrus and proestrus stages. In early pregnancy (days 13-16), TNF immunolabelling was detected at the embryo-maternal surface, in the syncytium cords and the trophoblast, as well in the endometrial stroma and the basal endometrial glands, but not in the lacunar epithelium. The overall TNF immunoreactivity was higher in early pregnancy samples in comparison with those of the early dioestrus and dioestrus stages, suggesting it plays a role during implantation.

© 2010 Blackwell Verlag GmbH.

PMID 20880318

The IGF1 small dog haplotype is derived from Middle Eastern grey wolves

Total neuron numbers in CA1-4 sectors of the dog hippocampus

Indian J Med Res. 2010 Jun;131:780-5.

Rağbetli MC, Aydinlioğlu A, Koyun N, Yayici R, Arslan K. Departments of Histology & Embryology , Medical Faculty, Yüzüncü Yil University,Van, Turkey. Abstract BACKGROUND & OBJECTIVES: Early reports addressed morphological asymmetry in the cross-sectional width of the rat hippocampus. The present study was aimed at counting total number of neurons in CA1-4 sectors and the subiculum of the dog hippocampus as well as investigating possible left /right and male/female asymmetry. METHODS: Adult mongrel dogs (8 female and 5 male) were assessed by the right and left pawedness and sacrificed by exsanguinations. In each hippocampus dissected, the total neuron numbers of CAs and subiculum were estimated by the physical fractioning method. RESULTS: Significant hemispheric asymmetries were found in the number of pyramidal cells of CA1, CA3/2, CA4 and the subiculum. Sex difference was also found in the subiculum, in favour of the males. INTERPRETATION & CONCLUSION: Our study indicated a left dominant asymmetry in males and right dominancy in females as well as no functional asymmetry in specific regions of the dog hippocampus. Further investigations are necessary to verify the hypothesis that hippocampal morphological asymmetries in normal subjects are functionally related in memory or in cognitive skills.

PMID 20571166

Early Development and Putative Primordial Germ Cells Characterization in Dogs

Reprod Domest Anim. 2010 Apr 30.

Martins DS, Ambrósio CE, Saraiva NZ, Wenceslau CV, Morini AC, Kerkis I, Garcia JM, Miglino MA.

Faculty of Animal Science and Food Engineering, University of Sao Paulo, Pirassununga, Brazil.


Contents Previously, three distinct populations of putative primordial germ cells (PGCs), namely gonocytes, intermediate cells and pre-spermatogonia, have been described in the human foetal testis. According to our knowledge, these PGCs have not been studied in any other species. The aim of our study was to identify similar PGC populations in canine embryos. First, we develop a protocol for canine embryo isolation. Following our protocol, 15 canine embryos at 21-25 days of pregnancy were isolated by ovaryhysterectomy surgery. Our data indicate that dramatic changes occur in canine embryo development and PGCs specification between 21 to 25 days of gestation. At that moment, only two PGC populations with distinct morphology can be identified by histological analyses. Cell population 1 presented round nuclei with prominent nucleolus and a high nuclear to cytoplasm ratio, showing gonocyte morphology. Cell population 2 was often localized at the periphery of the testicular cords and presented typical features of PGC. Both germ cell populations were positively immunostained with anti-human OCT-4 antibody. However, at day 25, all cells of population 1 reacted positively with OCT-4, whereas in population 2, fewer cells were positive for this marker. These two PGCs populations present morphological features similar to gonocytes and intermediate cells from human foetal testis. It is expected that a population of pre-spermatogonia would be observed at later stages of canine foetus development. We also showed that anti-human OCT-4 antibody can be useful to identify canine PGC in vivo.

PMID 20477984

Some embryological aspects of cholinergic innervation in the cardiovascular system--a close association with the subintestinal circulatory channel

J Pharmacol Sci. 2010 Apr;112(4):383-96. Epub 2010 Mar 30.

Shigei T, Tsuru H, Ishikawa N, Yoshioka K. Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Japan.


A series of our studies on the dog venous system revealed that cholinergic excitatory innervation was localized in a group of veins: the portal, mesenteric, and hepatic veins and the middle segment of the inferior vena cava. Our studies on pharmacological responsiveness of dog veins also revealed that they could be divided into two groups: the visceral and somatic parts, and the cholinergic excitatory innervation localized to the visceral part. Considering these results and some relevant literature, a hypothesis is proposed on the classification of muscles of the cardiovascular system and some embryological aspects of the parasympathetic cholinergic innervation in the circulatory system are discussed. The embryonic circulatory system of vertebrates can be divided into two parts: somatic and visceral. The body of an embryo is regarded as a double tube and vessels of the visceral part and the heart belong to the inner tube. The muscle of these vessels and the heart are derived from visceral mesoderm, either the coelomic epithelium or mesenchymal cells, in common with muscle of the digestive tube; and thus the parasympathetic cholinergic nerves innervating the muscle of the digestive tube also distribute to these vessels and the heart. The heart and vascular muscles in the visceral part are structures developed early in the course of evolution in invertebrates. Their primary function is to propel the body fluid, and the chief structure containing them is the subintestinal circulatory channel (ventral aorta - heart - subintestinal vein). They exhibit spontaneous, rhythmic activity, showing characteristics of a single unit muscle, and receive parasympathetic cholinergic innervation. On the other hand, the vascular muscles in the somatic part are endothelium-associated muscles developed anew in the vertebrate; do not contract spontaneously, being classified as a multiunit muscle; and lack parasympathetic cholinergic innervation.

PMID 20351483

Comparative study of Pax2 expression in glial cells in the retina and optic nerve of birds and mammals

J Comp Neurol. 2010 Jun 15;518(12):2316-33.

Stanke J, Moose HE, El-Hodiri HM, Fischer AJ. Integrated Biomedical Science Graduate Program, College of Medicine, The Ohio State University, Columbus, Ohio 43210, USA.


Little is known about the expression of Pax2 in mature retina or optic nerve. Here we probed for the expression of Pax2 in late stages of embryonic development and in mature chick retina. We find two distinct Pax2 isoforms expressed by cells within the retina and optic nerve. Surprisingly, Müller glia in central regions of the retina express Pax2, and levels of expression are decreased with increasing distance from the nerve head. In Müller glia, the expression levels of Pax2 are increased by acute retinal damage or treatment with growth factors. At the optic nerve, Pax2 is expressed by peripapillary glia, at the junction of the neural retina and optic nerve head and by glia within the optic nerve. In addition, we assayed for Pax2 expression in glial cells in mammalian retinas. In mammalian retinas, unlike the case in chick retina, the Müller glia do not express Pax2. Pax2-expressing cells are found in the optic nerve and astrocytes within the mouse retina. By comparison, Pax2-positive cells are not found within the guinea pig retina; Pax2-expressing glia are confined to the optic nerve. In dog and monkey (Macaca fascicularis), Pax2 is expressed by astrocytes that are scattered across inner retinal layers and by numerous glia within the optic nerve. Interestingly, Pax2-positive glial cells are found at the peripheral edge of the dog retina, but only in older animals. We conclude that the expression of Pax2 in the vertebrate eye is restricted to retinal astrocytes, peripapillary glia, and glia within the optic nerve. Copyright 2010 Wiley-Liss, Inc.

PMID 20437530

Localization of canine brachycephaly using an across breed mapping approach

PLoS One. 2010 Mar 10;5(3):e9632.

Bannasch D, Young A, Myers J, Truvé K, Dickinson P, Gregg J, Davis R, Bongcam-Rudloff E, Webster MT, Lindblad-Toh K, Pedersen N. Source Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.


The domestic dog, Canis familiaris, exhibits profound phenotypic diversity and is an ideal model organism for the genetic dissection of simple and complex traits. However, some of the most interesting phenotypes are fixed in particular breeds and are therefore less tractable to genetic analysis using classical segregation-based mapping approaches. We implemented an across breed mapping approach using a moderately dense SNP array, a low number of animals and breeds carefully selected for the phenotypes of interest to identify genetic variants responsible for breed-defining characteristics. Using a modest number of affected (10-30) and control (20-60) samples from multiple breeds, the correct chromosomal assignment was identified in a proof of concept experiment using three previously defined loci; hyperuricosuria, white spotting and chondrodysplasia. Genome-wide association was performed in a similar manner for one of the most striking morphological traits in dogs: brachycephalic head type. Although candidate gene approaches based on comparable phenotypes in mice and humans have been utilized for this trait, the causative gene has remained elusive using this method. Samples from nine affected breeds and thirteen control breeds identified strong genome-wide associations for brachycephalic head type on Cfa 1. Two independent datasets identified the same genomic region. Levels of relative heterozygosity in the associated region indicate that it has been subjected to a selective sweep, consistent with it being a breed defining morphological characteristic. Genotyping additional dogs in the region confirmed the association. To date, the genetic structure of dog breeds has primarily been exploited for genome wide association for segregating traits. These results demonstrate that non-segregating traits under strong selection are equally tractable to genetic analysis using small sample numbers.

PMID 20224736


Follicular morphology, oocyte diameter and localisation of fibroblast growth factors in the domestic dog ovary

Reprod Domest Anim. 2009 Jul;44 Suppl 2:65-70.

Songsasen N, Fickes A, Pukazhenthi BS, Wildt DE.

Department of Reproductive Sciences, Center for Species Survival, Smithsonian's National Zoological Park, Front Royal, VA 22630, USA. Abstract Remarkably little is known about folliculogenesis in the dog. Objectives were to characterise (1) changes in follicle/oocyte diameter and granulosa cell number and (2) localisation of fibroblast growth factor (FGF)-2 and FGF-7 during dog ovarian follicle development. Fourteen ovarian pairs were excised and processed for histological evaluation. Two to four serial sections/bitch were stained with hematoxylin, and follicle/oocyte diameters and granulosa cell number were determined at each developmental stage. Mean follicle and oocyte size were compared among stages by one-way analysis of variance. Relationships between follicle and oocyte size and granulosa cell number were determined using correlation and regression analysis, respectively. Another eight serial sections/bitch were processed for immunostaining to determine FGF-2 and FGF-7 localisation. Primordial and primary follicles were similar in size, but smaller than the progressively increasing (p < 0.05) diameter of the later stages. Oocyte diameter gradually increased (p < 0.05) among oocytes derived from primordial, primary, secondary and early antral follicles with no difference (p > 0.05) thereafter. Oocyte size and granulosa cell number increased (p < 0.01) with follicular diameter. Except during anoestrus, FGF-2 occurred in oocytes and granulosa cells of primordial to secondary follicles. In adult bitches, FGF-7 was localised in granulosa cells of primary and secondary follicles and also occurred in the theca layer of antral follicles during prooestrus and oestrus. In summary, folliculogenesis in the domestic dog occurs in two phases: pre-antral phase characterised by increasing follicle size in association with oocyte growth and granulosa cell proliferation and antral phase linked with marked granulosa cell proliferation and accumulation of antral cavity fluid. Finally, the temporal localisation pattern of FGF-2 implies its role in follicular activation, whereas FGF-7 activities appear related to later folliculogenesis.

PMID 19754538

Endocrinologic control of normal canine ovarian function

Reprod Domest Anim. 2009 Jul;44 Suppl 2:3-15.

Concannon PW.

Department of Biological Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.

Abstract In dogs, the termination of the 3-10-month obligate anoestrus involves selection of a cohort of LH-sensitive follicles, presumably from a wave of dominant small antral follicles that would otherwise undergo atresia. The number and size of such follicles appears to increase, especially during the last 50 days of anoestrus when the already elevated concentrations of FSH become further elevated. The final selection and eventual terminal development of these follicles is caused by an increased frequency of high-amplitude LH pulses at the end of anoestrus. Concomitant increases in FSH are typically small or negligible. High concentrations of FSH in anoestrus are likely to be important in maintaining, if not stimulating, overlapping waves of dominant follicles throughout anoestrus, their expression of aromatase activity and basal oestradiol secretion sufficient to suppress LH by negative feedback. An attractive hypothesis is that late anoestrus increases in LH-stimulate synthesis of precursor androgen for already available FSH-dependent aromatase. After 7 or more days of elevated LH, and perhaps 2-5 days of semi-autonomous growth, with maximal oestradiol production reached, follicle capacity to further increase oestradiol becomes limited and excess progesterone becomes increasingly secreted. The pre-ovulatory LH surge and oestrus onset are then triggered - often synchronously and in concert with the terminal maturation of the follicles - by central effects of the large decrease in the oestrogen to progestin ratio. Follicular endocrine and paracrine events during and following the LH surge are likely similar to those reported for other species. The prolonged luteal phase lengths of 55-75 days in non-pregnant bitches bracket the 64 +/- 1 day in pregnancy and represent a genetically programmed luteal cell lifespan approximating gestation length as occurs in the luteal phase of hysterectomized animals of most polyoestrous artiodactyls and rodents. The 30-40-day slow regression after day 20 to 30 involves periodic cell death, diminution in cell size, low levels of apoptosis and minimal or modest involvement of endogenous prostaglandin F (PGF) production. The canine corpus luteum (CL) is dependent on both LH and prolactin as stimulating luteotrophins by day 15, and as required luteotrophins by days 20-25, if not earlier. Thereafter, both luteotrophins likely have cellular mechanisms of action similar to those reported for other species. Progesterone secretion during pregnancy is greatly enhanced by characteristic, and probably relaxin-stimulated, increases in prolactin concentration starting at or after day 25, and persisting to term. Near term, foetoplacental maturation results in the placental release of large, luteolytic amounts of PGF for 1-2 days pre-partum. Pre-partum luteolysis, like that induced by exogenous prostaglandin, likely involves a cascade enhanced by the removal of progesterone inhibition of PGF release and some degree of intra-luteal PGF synthesis. That a likely twofold or greater increase in progesterone production by the CL of pregnancy does not result in significantly higher serum progesterone than in non-pregnant metoestrus relates to several biological changes, including a large increase in plasma volume of distribution, increased metabolism of progesterone by increased uterine, placental and mammary masses and increased liver clearance and excretion of progesterone and progesterone metabolite. Anoestrus length and ovarian cycle intervals, variable within and among bitches, are likely affected by neuroendocrine components of an endogenous circannual cycle, albeit only photo-entrained in the Basenji breed. This may be modified by the prior luteal phase, exposure to oestrus female pheromones and as yet unknown mechanisms that likely operate via inhibitory opioidergic and/or stimulatory dopaminergic hypothalamic pathways affecting late anoestrus increases in LH.

PMID: 19754529

Prolonged duration of fertility of dog ova

Reprod Domest Anim. 2009 Jul;44 Suppl 2:230-3.

Tsutsui T, Takahashi F, Hori T, Kawakami E, Concannon PW.

Department of Reproduction, Nippon Veterinary and Life Science University, Musahino, Tokyo, Japan. Abstract The fertile period for natural mating in dogs extends from before ovulation until day 5 post ovulation (PO) and involves a delay in oocyte maturation until 2-3 days PO and viability of secondary oocytes for 48-60 h or more. Spermatozoa do not enter the uterus after vaginal insemination in late oestrus. Cervical closure appears to occur on average 5 days PO, but conception may occur following intrauterine artificial insemination (IUAI) up to 8 days PO. Therefore, the present study was conducted to clarify the duration of fertility of canine ova. Using IUAI at 6, 7, 8 and 9 days PO (n = 5 bitches each) conception rates were 100%, 71.4%, 37.5% and 0%, respectively, with an average litter resorption rate of 30.8%, and with mean litter sizes and times to delivery PO being 4.3 +/- 1.6 and 64.3 +/- 0.3 days, 4.0 +/- 1.4 and 66.3 +/- 0.4 days, and 2.5 and 68 days for IUAI at 6, 7 and 8 days, respectively. The high pregnancy rates with IUAI at 6 and 7 days PO confirm that many canine oocytes are fertile at 4-5 days after maturation. The high rate of resorption was presumably because of aging of ova or asynchrony between embryonic development and the intrauterine environment.

PMID: 19754575

Complex cardiac congenital defects in an adult dog: an ultrasonographic and magnetic resonance imaging study

Can Vet J. 2009 Sep;50(9):933-5.

García-Rodríguez MB, Granja MA, García CC, Gonzalo Orden JM, Cano Rábano MJ, Prieto ID. Department of Veterinary Medicine, Surgery and Anatomy, Veterinary Faculty, University of León, Campus de Vegazana, s/n. 24007, León, Spain. Abstract This article describes a complex and not previously reported combination of congenital cardiac defects. Echocardiography showed dilation of right and left chambers, accompanied with patent ductus arteriosus, persistence of the left cranial vena cava, atrial septal defect (ASD), subaortic stenosis, and tricuspid dysplasia. The interatrial wall was examined and the diameter of the ASD was measured by magnetic resonance imaging (MRI). PMID 19949552

Congenital heart defects represent one of the most frequent causes of mortality in stillborn dogs and puppies less than 1 year old (1). A retrospective analysis showed that cardiac congenital defects were 23.5% of the total cardiac disease cases (2). The coexistence of ≥ 2 cardiac malformations can be defined as complex congenital heart disease. Their prevalence has been reported as 8.2% and 9.5% of cardiac congenital defects

Preliminary study in immature canine oocytes stained with brilliant cresyl blue and obtained from bitches with low and high progesterone serum profiles

Reprod Domest Anim. 2009 Jul;44 Suppl 2:255-8.

Rodrigues BA, Rodriguez P, Silva AE, Cavalcante LF, Feltrin C, Rodrigues JL. Laboratory of Embryology and Biotechnics of Reproduction, Faculty of Veterinary Medicine, UFRGS, Porto Alegre, RS, Brazil. Abstract This study was conducted: (i) to observe the features and levels of blue colour impregnation in morphologically selected immature canine cumulus oocyte complexes (COCs) stained with the brilliant cresyl blue (BCB) dye, as indicators of quality, and integrity of nuclear oocyte chromatin configuration before in vitro maturation (IVM); (ii) to observe the relationship between the influence of serum progesterone (SP) concentrations from ovary donors and BCB staining of immature dog oocytes. The results showed that out of 138 canine COCs, germinal vesicle (GV) stage prevailed in BCB+ oocytes at percentages of 67.4% (60/89), which were statistically higher than those observed in BCB+/- (52.2%; 23/44) and BCB- (20%; 1/5) oocytes (p = 0.023). Oocytes BCB+ were interpreted as those having completed their growth and therefore possessing the capacity to mature and develop in vitro. Ooplasm and cumulus cells (CCs) of canine oocytes were BCB staining independent. Ooplasm blue colour staining reaction varied between grown oocytes, revealing different levels of glucose-6-phosphate dehydrogenase activity among and within oocytes. Additionally, SP profile of ovary donors was not a relevant indicator for selection of oocytes screened with the BCB stain. Similar numbers of high quality oocytes were observed to be BCB+, BCB+/- and BCB- between groups of females with SP varying from 0 to 2.5 ng/ml (n = 5), and those with SP varying from 2.6 to 16.7 ng/ml (n = 4) (p = 0.680). It may be inferred that bitches with low and high SP profiles have grown oocytes in their ovaries, as determined by the BCB absorbance in their ooplasms.

PMID 1975458

Birth of Beagle dogs by somatic cell nuclear transfer

Anim Reprod Sci. 2009 Sep;114(4):404-14. Epub 2008 Oct 22.

Hossein MS, Jeong YW, Park SW, Kim JJ, Lee E, Ko KH, Hyuk P, Hoon SS, Kim YW, Hyun SH, Shin T, Hwang WS. SooAm Biotech Research Foundation, 1024-39 Saam-Ri, Wonsam-Myeon, Cheoin-Gu, Yongin-Si, Gyeonggi-Do 449-872, Republic of Korea.


The present study was undertaken to evaluate two enucleation methods for somatic cell nuclear transfer (SCNT), and to standardize the optimum number of embryos for transfer to each recipient for canines. Oocytes retrieved from outbreed dogs were reconstructed with adult somatic cells from a male Beagle dog. A total of 134 or 267 oocytes were enucleated either by aspiration or squeezing method, fused with two DC pulses of 1.75 kV/cm for 15 micros electrical stimulation, chemically activated after 1h of fusion using 10 microM calcium ionophore for 4 min and cultured 4h in 1.9 mM 6-dimethylaminopurine. Finally, 103 or 214 embryos for aspiration or squeezing method were transferred to 6 or 11 naturally synchronized recipients, respectively. A total of 53, 317 and 342 embryos were transferred to 7, 17 and 12 recipients for the group of 4-10, 11-25 and 26-40 embryos, respectively. There was no difference between fusion rate (76.87% vs. 80.15%), full term pregnancy rate (16.66% vs. 27.27%) and percent of live puppies born (0.97% vs. 1.87%) for aspiration and squeezing method (P>0.05). Production efficiency of cloned dogs was significantly affected by the number of embryos transferred to each recipient. No pregnancy was established for the group of 4-10 embryos (n=7) and 26-40 embryos (n=12) while pregnancy was detected in 23.53% recipients received a group of 11-25 embryos (n=17). Among them, five (1.76%) live puppies were born (P<0.05). These data show an increase in the overall efficiency of SCNT in canine species.

PMID 19059739

The genomic architecture of segmental duplications and associated copy number variants in dogs

Genome Res. 2009 Mar;19(3):491-9. Epub 2009 Jan 7.

Nicholas TJ, Cheng Z, Ventura M, Mealey K, Eichler EE, Akey JM. Source Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.


Structural variation is an important and abundant source of genetic and phenotypic variation. Here we describe the first systematic and genome-wide analysis of segmental duplications and associated copy number variants (CNVs) in the modern domesticated dog, Canis familiaris, which exhibits considerable morphological, physiological, and behavioral variation. Through computational analyses of the publicly available canine reference sequence, we estimate that segmental duplications comprise approximately 4.21% of the canine genome. Segmental duplications overlap 841 genes and are significantly enriched for specific biological functions such as immunity and defense and KRAB box transcription factors. We designed high-density tiling arrays spanning all predicted segmental duplications and performed aCGH in a panel of 17 breeds and a gray wolf. In total, we identified 3583 CNVs, approximately 68% of which were found in two or more samples that map to 678 unique regions. CNVs span 429 genes that are involved in a wide variety of biological processes such as olfaction, immunity, and gene regulation. Our results provide insight into mechanisms of canine genome evolution and generate a valuable resource for future evolutionary and phenotypic studies.

PMID 19129542

Mapping DNA structural variation in dogs

Genome Res. 2009 Mar;19(3):500-9. Epub 2008 Nov 17.

Chen WK, Swartz JD, Rush LJ, Alvarez CE. Source Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205, USA. Erratum in Genome Res. 2009 Apr;19(4):690.


DNA structural variation (SV) comprises a major portion of genetic diversity, but its biological impact is unclear. We propose that the genetic history and extraordinary phenotypic variation of dogs make them an ideal mammal in which to study the effects of SV on biology and disease. The hundreds of existing dog breeds were created by selection of extreme morphological and behavioral traits. And along with those traits, each breed carries increased risk for different diseases. We used array CGH to create the first map of DNA copy number variation (CNV) or SV in dogs. The extent of this variation, and some of the gene classes affected, are similar to those of mice and humans. Most canine CNVs affect genes, including disease and candidate disease genes, and are thus likely to be functional. We identified many CNVs that may be breed or breed class specific. Cluster analysis of CNV regions showed that dog breeds tend to group according to breed classes. Our combined findings suggest many CNVs are (1) in linkage disequilibrium with flanking sequence, and (2) associated with breed-specific traits. We discuss how a catalog of structural variation in dogs will accelerate the identification of the genetic basis of canine traits and diseases, beginning with the use of whole genome association and candidate-CNV/gene approaches.

PMID 19015322

Non-rotated midgut in a dog

Anat Histol Embryol. 2009 Feb;38(1):58-61. Epub 2008 Oct 18.

Kirk EJ, Nutman AW, Murray SL. Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag, Palmerston North, New Zealand. Abstract Macroscopic observations of the partly-dissected abdomen of the preserved cadaver of a Labrador bitch were recorded and photographs taken. Neither the duodenum nor the colon looped around the root of the great (jejuno-ileal) mesentery, but both were long enough to have done so. The abdominal organs appeared to be otherwise normal, as did the other parts of the body. The condition appeared to have resulted from non-rotation of the midgut during embryonic development and to have no adverse effect on the animal. PMID 18983624


Germinal vesicle chromatin configuration and meiotic competence is related to the oocyte source in canine

Anim Reprod Sci. 2008 Jan 30;103(3-4):336-47. Epub 2006 Dec 17.

Lee HS, Yin XJ, Jin YX, Kim NH, Cho SG, Bae IH, Kong IK.

PMID 17212978

This study investigated the effect of deriving oocytes from different stages of the estrous cycle on oocyte diameter, germinal vesicle (GV) chromatin configuration, and in vitro meiotic competence in canine oocytes. Cumulus oocyte complexes (COCs) were recovered from both ovaries during anestrous, follicular, and luteal phases and in vivo ovulated oocytes. The diameter of canine oocyte was compared with or without the zona pellucida (ZP) before in vitro maturation (IVM). Also, GV chromatin configuration was evaluated before (0 h) or 72 h after IVM by fixation with 3.7% formaldehyde supplemented with 10 microg/ml Hoechst 33342 for 30 min. COCs were matured in TCM199 supplemented with 10% fetal bovine serum (FBS), 0.6 mM cysteine, 0.2 mM pyruvic acid, 50 microg/ml gentamycin sulfate, and 20 microg/ml 17beta-estradiol (E(2)) at 39 degrees C and 5% CO(2) in air for 72 h. The diameter of in vivo ovulated oocytes with the ZP (167.5+/-12.7 microm) or without ZP (133.9+/-5.3 microm) was significantly greater (p<0.05) than those of anestrous, follicular, and luteal oocytes (with ZP, 151.2+/-7.4, 153.1+/-8.8 and 152.8+/-5.4 microm, respectively; without ZP, 115.3+/-7.6, 122.1+/-4.9 and 114.3+/-6.6 microm, respectively). At 0 h, the GV-II configuration was more prevalent in oocytes from anestrual ovaries than from follicular or luteal ovaries or in vivo ovulated oocytes (63.6% versus 14.8%, 33.0%, and 0.0%; p<0.05), whereas the proportion of oocytes with the GV-V configuration was higher in follicular phase and ovulated oocytes than in oocytes from anestrus and luteal phase (57.4% and 100% versus 2.0% and 22.7%; p<0.05). However, oocytes in luteal phase exhibited diverse GV configurations (10.3%, 33.0%, 16.5%, 13.4%, and 22.7% in GV-I, GV-II, GV-III, GV-IV, and GV-V, respectively). After 72 h post-IVM, a greater percentage of in vivo ovulated oocytes progressed to MII than those oocytes collected during anestrous, follicular, and luteal phases (50.0% versus 5.5%, 11.5%, and 9.1%; p<0.05). In conclusion, the oocyte diameter, GV chromatin configuration, and meiotic maturation of canine COCs are related to the oocyte source. These results indicated that the oocyte source could be critical to nuclear progression to MII stage in canines.

Germinal vesicle chromatin configuration

  • GV-I - condensed filamentous chromatin clumps around the nuclear membrane
  • GV-II - localized filamentous chromatin clumps around the nucleolus
  • GV-III - distributed filamentous chromatin clumps in the nucleus and disappeared nucleolus
  • GV-IV - thick clumps of condensed chromatin
  • GV-V - a single clump of condensed chromatin
  • MII, apparent first polar body

Canine polydactyl mutations with heterogeneous origin in the conserved intronic sequence of LMBR1

Park K, Kang J, Subedi KP, Ha JH, Park C. Genetics. 2008 Aug;179(4):2163-72. Epub 2008 Aug 9.

Canine preaxial polydactyly (PPD) in the hind limb is a developmental trait that restores the first digit lost during canine evolution. Using a linkage analysis, we previously demonstrated that the affected gene in a Korean breed is located on canine chromosome 16. The candidate locus was further limited to a linkage disequilibrium (LD) block of <213 kb composing the single gene, LMBR1, by LD mapping with single nucleotide polymorphisms (SNPs) for affected individuals from both Korean and Western breeds. The ZPA regulatory sequence (ZRS) in intron 5 of LMBR1 was implicated in mammalian polydactyly. An analysis of the LD haplotypes around the ZRS for various dog breeds revealed that only a subset is assigned to Western breeds. Furthermore, two distinct affected haplotypes for Asian and Western breeds were found, each containing different single-base changes in the upstream sequence (pZRS) of the ZRS. Unlike the previously characterized cases of PPD identified in the mouse and human ZRS regions, the canine mutations in pZRS lacked the ectopic expression of sonic hedgehog in the anterior limb bud, distinguishing its role in limb development from that of the ZRS.

PMID 18689889

Canine preaxial polydactyly (PPD)


Immune system development in the dog and cat

J Comp Pathol. 2007 Jul;137 Suppl 1:S10-5. Epub 2007 Jun 8.

Day MJ. Division of Veterinary Pathology, Infection and Immunity, School of Clinical Veterinary Science, University of Bristol, Langford BS40 5DU, UK. Abstract Routine vaccination of young puppies and kittens takes place within the first 16 weeks of life, during which time there is considerable change in the immune system of these animals. Newborn pups and kittens must obtain passive immune protection through the ingestion of colostrum within the first hours of life. The timing of early life vaccination is determined by the period of time required for passively acquired immunoglobulin to degrade, thereby permitting an endogenous immune response to be generated by the neonate. In the absence of inhibitory maternally derived antibody (MDA), pups and kittens are capable of mounting a protective immune response at an early age. New generation molecular vaccines appear able to circumvent the inhibitory effects of MDA. In addition to changes in serum immunoglobulin concentrations, there are alterations in the numbers and proportions of blood and tissue leucocytes (particularly CD4(+) and CD8(+) T cells, and B cells) during the first year of life. The qualitative nature of the newborn immune system may also alter from Th2 regulation in utero to Th1 regulation in the neonatal period. Immune function is likely to be genetically determined, and in dogs there is evidence for breed effects on immune function which likely relate to the inheritance of particular haplotypes of major histocompatibility complex (MHC) genes. The design of vaccines for young animals of these species must take into account these immunological changes and the potential modulatory effect of vaccines on immune development.

PMID 17560591

Breed relationships facilitate fine-mapping studies: a 7.8-kb deletion cosegregates with Collie eye anomaly across multiple dog breeds

Parker HG, Kukekova AV, Akey DT, Goldstein O, Kirkness EF, Baysac KC, Mosher DS, Aguirre GD, Acland GM, Ostrander EA. Genome Res. 2007 Nov;17(11):1562-71. Epub 2007 Oct 4.

The features of modern dog breeds that increase the ease of mapping common diseases, such as reduced heterogeneity and extensive linkage disequilibrium, may also increase the difficulty associated with fine mapping and identifying causative mutations. One way to address this problem is by combining data from multiple breeds segregating the same trait after initial linkage has been determined. The multibreed approach increases the number of potentially informative recombination events and reduces the size of the critical haplotype by taking advantage of shortened linkage disequilibrium distances found across breeds. In order to identify breeds that likely share a trait inherited from the same ancestral source, we have used cluster analysis to divide 132 breeds of dog into five primary breed groups. We then use the multibreed approach to fine-map Collie eye anomaly (cea), a complex disorder of ocular development that was initially mapped to a 3.9-cM region on canine chromosome 37. Combined genotypes from affected individuals from four breeds of a single breed group significantly narrowed the candidate gene region to a 103-kb interval spanning only four genes. Sequence analysis revealed that all affected dogs share a homozygous deletion of 7.8 kb in the NHEJ1 gene. This intronic deletion spans a highly conserved binding domain to which several developmentally important proteins bind. This work both establishes that the primary cea mutation arose as a single disease allele in a common ancestor of herding breeds as well as highlights the value of comparative population analysis for refining regions of linkage.

PMID 17916641


Embryo production in dogs: from in vitro fertilization to cloning

Reprod Domest Anim. 2006 Aug;41(4):286-90.

Luvoni GC, Chigioni S, Beccaglia M. Department of Veterinary Clinical Sciences, Obstetrics and Gynaecology, University of Milan, Milan, Italy. Abstract Increased availability of canine embryos would be desirable to develop research and to apply assisted reproductive technologies in the treatment of infertility and in the improvement of reproductive performances in valuable Canids, both domestic and non-domestic. Embryo production through in vitro fertilization and nuclear transfer has been technically achieved in the dog, and the transfer of cloned embryos has recently resulted in the birth of puppies. However, the efficiency of these technologies is still very limited. This is mainly because of the peculiar characteristics of the canine oocyte and the lack of its full acquisition of developmental competence in vitro. This paper discusses the latest results and aspects on which further research should be focused to provide advances in the field.

PMID 16869883

The carnivore pregnancy: the development of the embryo and fatal membranes

Theriogenology. 2006 Oct;66(6-7):1699-702. Epub 2006 Mar 23.

Miglino MA, Ambrósio CE, dos Santos Martins D, Wenceslau CV, Pfarrer C, Leiser R. Source Faculdade de Medicina Veterinária e Zootecnia, University of São Paulo, Brazil.


The aim of this research was to compare the morphological aspects during the development of pregnancy in dogs and cats, distinguishing features of the fetal membranes, such as yolk sac evolution and differentiation of hemangioblasts, and the degree of elaboration of the amnion and allantois. Canine and feline placentae from 20, 24, 35, 45 and 55 d of pregnancy were perfusion-fixed for histological investigation and vascular corrosion casts were produced. The casts were prepared for scanning electron microscopy (SEM) and the embryo and fetal membrane development was analyzed. The growth patterns of the conceptuses were compared with the organization of the placentation process, and changes of the morphology during pregnancy were recorded. In feline placentae, an incomplete zonary shape was present in 62.5% out of 60 studied cases. This was located distal to the insertion of the umbilical cord. In the lamellar zone, the interhemal membrane or placental barrier resembled endotheliochorial conditions, and the maternal-fetal microvascular blood flow interrelationship was of simple crosscurrent type. Dogs have a zonary placenta, completely surrounding the fetus, and complex lamellar organization of maternal and fetal tissues. At the border, two marginal hematomes with green colouration delimited the central placental girdle. The yolk sac consisted of one large sacculation with an inverted "T" shape and an enormous number of blood vessels; it had hemangioblast cells in contact with the epithelium. The amnion was avascular in early stages, but became vascularized by blood vessels of the internal allantoic membrane in later stages of pregnancy by intrinsic relation.

PMID 16563485

Genetic architecture of the dog: sexual size dimorphism and functional morphology

Trends Genet. 2006 Oct;22(10):537-44. Epub 2006 Aug 24.

Lark KG, Chase K, Sutter NB.

Department of Biology, University of Utah, Salt Lake City, UT 84112-0840, USA. Erratum in:

Trends Genet. 2007 Jan;23(1):25. Abstract Purebred dogs are a valuable resource for genetic analysis of quantitative traits. Quantitative traits are complex, controlled by many genes that are contained within regions of the genome known as quantitative trait loci (QTL). The genetic architecture of quantitative traits is defined by the characteristics of these genes: their number, the magnitude of their effects, their positions in the genome and their interactions with each other. QTL analysis is a valuable tool for exploring genetic architecture, and highlighting regions of the genome that contribute to the variation of a trait within a population.

PMID 16934357


Genome sequence, comparative analysis and haplotype structure of the domestic dog

Nature. 2005 Dec 8;438(7069):803-19.

Lindblad-Toh K, Wade CM, Mikkelsen TS, Karlsson EK, Jaffe DB, Kamal M, Clamp M, Chang JL, Kulbokas EJ 3rd, Zody MC, Mauceli E, Xie X, Breen M, Wayne RK, Ostrander EA, Ponting CP, Galibert F, Smith DR, DeJong PJ, Kirkness E, Alvarez P, Biagi T, Brockman W, Butler J, Chin CW, Cook A, Cuff J, Daly MJ, DeCaprio D, Gnerre S, Grabherr M, Kellis M, Kleber M, Bardeleben C, Goodstadt L, Heger A, Hitte C, Kim L, Koepfli KP, Parker HG, Pollinger JP, Searle SM, Sutter NB, Thomas R, Webber C, Baldwin J, Abebe A, Abouelleil A, Aftuck L, Ait-Zahra M, Aldredge T, Allen N, An P, Anderson S, Antoine C, Arachchi H, Aslam A, Ayotte L, Bachantsang P, Barry A, Bayul T, Benamara M, Berlin A, Bessette D, Blitshteyn B, Bloom T, Blye J, Boguslavskiy L, Bonnet C, Boukhgalter B, Brown A, Cahill P, Calixte N, Camarata J, Cheshatsang Y, Chu J, Citroen M, Collymore A, Cooke P, Dawoe T, Daza R, Decktor K, DeGray S, Dhargay N, Dooley K, Dooley K, Dorje P, Dorjee K, Dorris L, Duffey N, Dupes A, Egbiremolen O, Elong R, Falk J, Farina A, Faro S, Ferguson D, Ferreira P, Fisher S, FitzGerald M, Foley K, Foley C, Franke A, Friedrich D, Gage D, Garber M, Gearin G, Giannoukos G, Goode T, Goyette A, Graham J, Grandbois E, Gyaltsen K, Hafez N, Hagopian D, Hagos B, Hall J, Healy C, Hegarty R, Honan T, Horn A, Houde N, Hughes L, Hunnicutt L, Husby M, Jester B, Jones C, Kamat A, Kanga B, Kells C, Khazanovich D, Kieu AC, Kisner P, Kumar M, Lance K, Landers T, Lara M, Lee W, Leger JP, Lennon N, Leuper L, LeVine S, Liu J, Liu X, Lokyitsang Y, Lokyitsang T, Lui A, Macdonald J, Major J, Marabella R, Maru K, Matthews C, McDonough S, Mehta T, Meldrim J, Melnikov A, Meneus L, Mihalev A, Mihova T, Miller K, Mittelman R, Mlenga V, Mulrain L, Munson G, Navidi A, Naylor J, Nguyen T, Nguyen N, Nguyen C, Nguyen T, Nicol R, Norbu N, Norbu C, Novod N, Nyima T, Olandt P, O'Neill B, O'Neill K, Osman S, Oyono L, Patti C, Perrin D, Phunkhang P, Pierre F, Priest M, Rachupka A, Raghuraman S, Rameau R, Ray V, Raymond C, Rege F, Rise C, Rogers J, Rogov P, Sahalie J, Settipalli S, Sharpe T, Shea T, Sheehan M, Sherpa N, Shi J, Shih D, Sloan J, Smith C, Sparrow T, Stalker J, Stange-Thomann N, Stavropoulos S, Stone C, Stone S, Sykes S, Tchuinga P, Tenzing P, Tesfaye S, Thoulutsang D, Thoulutsang Y, Topham K, Topping I, Tsamla T, Vassiliev H, Venkataraman V, Vo A, Wangchuk T, Wangdi T, Weiand M, Wilkinson J, Wilson A, Yadav S, Yang S, Yang X, Young G, Yu Q, Zainoun J, Zembek L, Zimmer A, Lander ES.

Broad Institute of Harvard and MIT, 320 Charles Street, Cambridge, Massachusetts 02141, USA. Comment in:

Nature. 2005 Dec 8;438(7069):745-6. Abstract Here we report a high-quality draft genome sequence of the domestic dog (Canis familiaris), together with a dense map of single nucleotide polymorphisms (SNPs) across breeds. The dog is of particular interest because it provides important evolutionary information and because existing breeds show great phenotypic diversity for morphological, physiological and behavioural traits. We use sequence comparison with the primate and rodent lineages to shed light on the structure and evolution of genomes and genes. Notably, the majority of the most highly conserved non-coding sequences in mammalian genomes are clustered near a small subset of genes with important roles in development. Analysis of SNPs reveals long-range haplotypes across the entire dog genome, and defines the nature of genetic diversity within and across breeds. The current SNP map now makes it possible for genome-wide association studies to identify genes responsible for diseases and traits, with important consequences for human and companion animal health.

PMID 16341006


Dog star rising: the canine genetic system

Nat Rev Genet. 2004 Dec;5(12):900-10.

Sutter NB, Ostrander EA.

National Human Genome Research Institute, National Institutes of Health, 50 South Drive, MSC8002, Building 50, Room 5222, Bethesda, Maryland 20892, USA. Abstract Purebred dogs are providing invaluable information about morphology, behaviour and complex diseases, both of themselves and humans, by supplying tractable populations in which to map genes that control those processes. The diversification of dog breeds has led to the development of breeds enriched for particular genetic disorders, the mapping and cloning of which have been facilitated by the availability of the canine genome map and sequence. These tools have aided our understanding of canine population genetics, linkage disequilibrium and haplotype sharing in the dog, and have informed ongoing efforts of the need to identify quantitative trait loci that are important in complex traits.

PMID 15573122

Characterization of the canine desmin (DES) gene and evaluation as a candidate gene for dilated cardiomyopathy in the Dobermann

Stabej P, Imholz S, Versteeg SA, Zijlstra C, Stokhof AA, Domanjko-Petric A, Leegwater PA, van Oost BA. Gene. 2004 Oct 13;340(2):241-9.

Canine-dilated cardiomyopathy (DCM) in dogs is a disease of the myocardium associated with dilatation and impaired contraction of the ventricles and is suspected to have a genetic cause. A missense mutation in the desmin gene (DES) causes DCM in a human family. Human DCM closely resembles the canine disease. In the present study, we evaluated whether DES gene mutations are responsible for DCM in Dobermann dogs. We have isolated bacterial artificial chromosome clones (BACs) containing the canine DES gene and determined the chromosomal location by fluorescence in situ hybridization (FISH). Using data deposited in the NCBI trace archive and GenBank, the canine DES gene DNA sequence was assembled and seven single nucleotide polymorphisms (SNPs) were identified. From the canine DES gene BAC clones, a polymorphic microsatellite marker was isolated. The microsatellite marker and four informative desmin SNPs were typed in a Dobermann family with frequent DCM occurrence, but the disease phenotype did not associate with a desmin haplotype. We concluded that mutations in the DES gene do not play a role in Dobermann DCM. Availability of the microsatellite marker, SNPs and DNA sequence reported in this study enable fast evaluation of the DES gene as a DCM candidate gene in other dog breeds with DCM occurrence.

PMID 15475165


Sry and Sox9 expression during canine gonadal sex determination assayed by quantitative reverse transcription-polymerase chain reaction

Mol Reprod Dev. 2003 Aug;65(4):373-81.

Meyers-Wallen VN.

James A. Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.

Abstract Testis induction is associated with gonadal Sry and Sox9 expression in mammals, and with Sox9 expression in vertebrates where Sry is absent. In mammals, Sry might initiate testis induction by upregulating Sox9 expression; however, direct evidence supporting this hypothesis is lacking. Models of Sry-negative XX sex reversal (XXSR), in which testes develop in the absence of Sry, could provide the link between Sry and Sox9 in testis induction. To define the stages at which testis determination occurs in the canine model, Sry and Sox9 expression were measured in normal urogenital ridges (UGR) and gonads by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Testicular Sry expression rose continuously during canine developmental ages comparable to human carnegie stages (CS) 16-18, with maximal expression at CS 18. Sox9 was expressed in both male and female canine UGR up to CS 17, at which time testis expression became tenfold greater than in the ovary. Although Sox9 was detected by qRT-PCR in ovaries and mesonephroi of both sexes, expression was detected only in canine testes by whole mount in situ hybridization (WMISH). The timing of Sry and Sox9 expression is consistent with a role in testis determination: Sry expression begins at CS 16 in testes, followed by upregulation of Sox9 expression at CS 17. The quantity and temporal and spatial patterns of Sry and Sox9 expression in normal canine gonads are similar to those in humans, sheep, and pigs. These studies should provide the basis for understanding the mechanism of testis induction in the canine model of Sry-negative XXSR.

Copyright 2003 Wiley-Liss, Inc.

PMID 12840810


Embryo development, hormonal requirements and maternal responses during canine pregnancy

J Reprod Fertil Suppl. 2001;57:169-79.

Concannon P, Tsutsui T, Shille V.

Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.

The events of canine gestation appear to occur consistently among bitches relative to the time of the preovulatory LH surge. The interval from fertilization to the eight-cell stage was 5 days after insemination before oocyte maturation and only 3 days following insemination after oocyte maturation. Sixteen-cell embryos were observed at day 11 (day 0 = day of the LH surge) after either early or late insemination. Apparently, embryonic cleavage between the two-cell and 16-cell stages occurs more rapidly after fertilization of more mature oocytes. This finding, together with the narrow window for fertilization, may explain why the duration of gestation is similar whether mating occurs before or a few days after oocyte maturation. Observations also indicate that cessation of migration and final situating of embryos occurs between day 16 and day 20 and that uterine lumen vesicles are > 1 mm in diameter at days 17-19; vesicles are > 2 mm in diameter and elongated to 3-6 mm by days 20-22. Some blastocyst enlargement occurs between day 14 and day 20, and expansion inside lemon-shaped uterine vesicles prevents flushing of intact embryos from the uterus after day 20 or 21. Blastocysts can be enclosed in the zona pellucida as late as day 19 and loss of zona pellucida with further expansion occurs on days 19-20. Uterine swellings can be observed in vivo, albeit inconsistently, at days 21-22 at the time of embryo attachment, and even before invasion of the embryo into the endometrium. The uterine responses to embryo localization may be detected via uterine transillumination by day 21, even in the absence of gross swelling. Blastocysts remain unattached as late as days 21-22; invasion of placental trophectoderm occurs as early as day 22 and as late as day 23, and only 1-2 days before heartbeats are detected by sonography. Assay of canine relaxin by canine relaxin-specific radioimmunoassay detected increases in serum relaxin concentrations as early as days 26-30 and no earlier than the concurrent increase in serum prolactin concentrations at days 26-30; the increase in serum relaxin concentrations was also no earlier than increases in the concentrations of serum acute phase proteins, including fibrinogen. It is not known whether relaxin can stimulate prolactin secretion in dogs. When natural progesterone alone was provided by injection and subcutaneous implants before and after ovariectomy performed before implantation, implantation occurred normally, and pregnancy was maintained to term. The increase in prolactin was not different from that of control pregnancy, despite the absence of effective systemic concentrations of oestrogen, as observed by a typical castration response in LH and FSH. Lack of oestrogen may have compromised mammary development and lactation. Therefore, the pregnancy-associated increase in prolactin concentrations does not require an increase in or the presence of maternal oestrogen. These observations extend our knowledge of canine pregnancy and indicate several areas worthy of further investigation.

PMID 11787146


Species-specific features of oestrous development and blastogenesis in domestic canine species

Valtonen M, Jalkanen L. J Reprod Fertil Suppl. 1993;47:133-7.

University of Kuopio, Veterinary Research Station, Finland. Abstract The reproductive physiology of taxonomically closely related species is usually very similar. The main difference in the reproduction of the dog and fox is the length of the different phases of the oestrous cycle. Pro-oestrus and oestrus are longest in the dog: oestrus lasts 3-5 days in the blue fox and 1-3 days in the silver fox, compared with about 1 week in the dog. The profiles of sex steroid concentrations in plasma during oestrus and pregnancy are similar and the luteal phase in non-pregnant animals is prolonged, progesterone concentrations reaching a maximum by 15-30 days after the luteinizing hormone (LH) peak in the dog, by 10-20 days in the blue fox and by 5-15 days in the silver fox. The duration from LH surge to ovulation is about the same in the dog and fox, but thereafter the oocytes and early embryos develop faster in foxes than in the dog. The tubal transport time is 4-6 days in the silver fox, embryos entering the uterus at the 4-16-cell stage. In the blue fox the oocytes remain in the oviducts for 8-10 days, developing into the morula stage, whereas in the dog a still longer oviductal phase results in embryos that are at the compact morula or blastocyst stage when entering the uterus. The preimplantation period is about 1 week in the dog and the blue fox, but 9-10 days in the silver fox.(ABSTRACT TRUNCATED AT 250 WORDS)

PMID 8229920

The critical period for mullerian duct regression in the dog embryo.

Biol Reprod. 1991 Oct;45(4):626-33.

Meyers-Wallen VN, Manganaro TF, Kuroda T, Concannon PW, MacLaughlin DT, Donahoe PK.

Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853-6401. Abstract The embryonic period during which Mullerian duct regression and Mullerian Inhibiting Substance (MIS) secretion occur was determined in canine embryos removed from timed pregnancies (32, 36, 37, 39, 42, and 46 days gestation). Sex chromosomes of each embryo were identified in metaphase spreads prepared from fibroblast cultures. Testicular differentiation, defined by seminiferous tubule formation and the presence of Sertoli cells and Leydig cells, and the degree of Mullerian duct regression were determined by careful morphologic analysis of histologic sections of canine embryonic gonads (n = 20) and Mullerian ducts (n = 20). MIS was detected immunohistochemically in embryonic testes using avidin-biotin complex enhancement of a specific rabbit polyclonal anti-MIS antibody. Testicular differentiation was observed at 36 days gestation. The earliest evidence of Mullerian duct regression in male embryos was observed at 36 days gestation, and regression was completed by 46 days gestation. Positive staining for MIS was present in testes from 36 to 46 days (n = 9). Staining was absent in the undifferentiated testis (n = 1) at 32 days gestation and in ovaries at all ages tested (n = 10). Thus, MIS is normally present throughout the critical period for Mullerian duct regression in the embryonic male dog.

PMID 1751638

  • Testicular differentiation was observed at 36 days gestation.
  • The earliest evidence of Mullerian duct regression in male embryos was observed at 36 days gestation, and regression was completed by 46 days gestation.
  • Positive staining for MIS was present in testes from 36 to 46 days (n = 9).
  • Staining was absent in the undifferentiated testis (n = 1) at 32 days gestation and in ovaries at all ages tested (n = 10).
  • Thus, MIS is normally present throughout the critical period for Mullerian duct regression in the embryonic male dog.

Changes in plasma androgen levels and testicular histology with descent of the testis in the dog

J Vet Med Sci. 1993 Dec;55(6):931-5.

Kawakami E, Yamada Y, Tsutsui T, Ogasa A, Yamauchi M.

Department of Reproduction, Nippon Veterinary and Animal Science University, Tokyo, Japan. Abstract Levels of 4-androstenedione (A), 5 alpha-dihydrotestosterone (DHT) and testosterone (T) in plasma collected from the heart or the jugular vein were measured in 61 male fetal dogs at between 38 and 60 days of gestation and 55 male neonatal dogs at between 0 and 50 days after birth. Testicular descent and histology were investigated after euthanasia of the fetuses and neonates. Although the testis still lay on the caudal ridge of the kidney in the 38- and 40-day-old fetuses, the gonad had slightly migrated from the kidney by 42 days of gestation. The testis approached the internal inguinal ring at Day 0 after birth and had passed through the inguinal canal at Day 5 after birth. The inguinal passage was the active phase of testicular descent. Both testes were drawn into the scrotum after 35 days of age. The number of gonocytes in the seminiferous cords had increased in the 58-day-old fetus, and Leydig cells in the stroma had become obvious because of morphological development and the formation of cell clumps. Plasma A levels in the male fetuses decreased temporarily after birth and plasma DHT increased provisionally at 54 and 58 days of gestation. Plasma T levels in the male neonates increased markedly after birth. These findings suggest that testicular descent in the dog fetus is accelerated by the DHT and T secretory function of the Leydig cells which increased after 54 days of gestation.

PMID 8117818

Biology of gonadotrophin secretion in adult and prepubertal female dogs

J Reprod Fertil Suppl. 1993;47:3-27.

Concannon PW.

Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853-6401. Abstract Studies in the female domestic dog demonstrate that luteinizing hormone (LH) and follicle-stimulating hormone (FSH) have secretion patterns that are pulsatile, are inhibited by oestradiol during pro-oestrus and surge to maximal values before ovulation. Studies in ovariectomized bitches suggest that the periovulatory surge is triggered by a preovulatory decline at late pro-oestrus in the oestrogen:progesterone ratio. During the 3-8-month non-seasonal anoestrus, FSH concentrations usually are 50-100% of those of the periovulatory peak, whereas LH concentrations are only 10-20% of peak values. In ovariectomized bitches FSH concentrations are often 5-10 times preovulatory peak values, whereas LH concentrations are only the same as, or double, peak values. Increased LH concentration and pulse frequency are associated with the termination of anoestrus. Treatment with gonadotrophin-releasing hormone (GnRH) pulses or infusions of GnRH agonists can induce fertile oestrus in early anoestrous bitches, as can treatment with a dopamine agonist, presumably by suppression of prolactin secretion. Between 4 months of age and pubertal pro-oestrus at 8-12 months of age, serum concentrations of FSH and LH are similar to those in adult anoestrus, and are suppressed during chronic infusion of GnRH agonist. The latter resulted in a reversible inhibition of puberty during 1 year of treatment. Studies in vivo have shown that LH and prolactin are luteotrophic throughout most of the luteal phase. LH stimulated progesterone synthesis by bitch luteal cells in vitro in the presence or absence of stimulant factors or steroid precursors present in serum.

PMID 8229941 The early brain development of the dog by ML Houston - 1968 - Cited by 5 - Related articles Philosophy degree in Zoology at Kansas State Univer- sity, Manhattan. 2 Kansas State Agriculture Experimental Station.

Ultrasonographic appearance of the uterus, placenta, fetus, and fetal membranes throughout accurately timed pregnancy in beagles

Am J Vet Res. 1972 Dec ;33 (12):2399-414

A E Yeager, H O Mohammed, V Meyers-Wallen, L Vannerson, P W Concannon

Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853. Serial ultrasonographic examinations were performed on 8 Beagle bitches from 20 to 60 days pregnant to determine time of first detection, appearance, and sizes of selected features of pregnancy. Gestation was timed from the day of the preovulatory luteinizing hormone surge. Findings related to gestational age were consistent among bitches. Gestational ages at earliest detection of the following features were: chorionic cavity at day 20; placental layers in the uterine wall at day 22 to 24; zonary placenta at day 27 to 30; embryo and heartbeat at day 23 to 25; yolk sac membrane at day 25 to 28; allantoic membrane at day 27 to 31; choroid plexus of the brain at day 31 to 35; fetal movement at day 34 to 36; skeleton at day 33 to 39; bladder and stomach at day 35 to 39; kidney at day 39 to 47; and liver hypoechoic, compared with lung, at day 38 to 42. Extra-fetal structures were measurable from day 20 or 22 through day 48. Chorionic cavity diameter increased from 0.2 +/- 0.0 cm to 3.3 +/- 0.2 cm, outer uterine diameter increased from 0.8 +/- 0.03 cm to 4.8 +/- 0.2 cm, length of chorionic cavity or zonary placenta increased from 0.3 +/- 0.03 cm to 4.9 +/- 0.05 cm, uterine wall thickness increased from 0.3 +/- 0.03 cm to 0.8 +/- 0.01 cm, and placental thickness increased from 0.1 +/- 0.0 cm to 0.5 +/- 0.05 cm. Chorionic cavity diameter, outer uterine diameter, and placental length each increased at a linear rate through day 37, after which time, each had a marked plateau in growth. Of the extra-fetal structures, chorionic cavity diameter was the most accurate for estimation of gestational age. All of the fetal structures studied increased at an increasing (second order) rate. Crown-rump length increased from 0.3 +/- 0.05 cm on day 24 to 9.2 +/- 0.2 cm on day 48. Body diameter increased from 0.2 +/- 0.03 cm on day 24 to 4.6 +/- 0.15 cm on day 60. Head diameter increased from 0.8 +/- 0.05 cm on day 34 to 2.7 +/- 0.04 cm on day 60. Of the fetal structures, head diameter was the most accurate for estimation of gestational age.

PMID 4641196

Morphological changes during ontogeny of the canine proximal colon

S M Ward, S Torihashi Department of Physiology, University of Nevada School of Medicine, Reno, NV 89557, USA. The development of the canine proximal colon from the completion of organogenesis through 43 days after birth was studied using light microscopy, immunofluorescence and electron microscopy. During this period the tunica muscularis increased in thickness from 42+/-6 microm in animals midway through the gestation period to 317+/-29 microm in animals 25-30 days old. This increase in thickness resulted from an increase in the number and size of smooth muscle cells in the circular and longitudinal muscle layers. The cross-sectional thickness of the circular muscle layer increased from 10+/-2 smooth muscle cells midway through the gestation period to 92+/-7 cells in animals 25-30 days old. The longitudinal layer increased in thickness from 1.5+/-1 cells in animals midway through the gestation period to 44+/-2 cells in animals 25-30 days old. Smooth muscle cells from both layers also increased in diameter and length. Ultrastructural and immunohistochemical studies suggested that many of the smooth muscle cells were undergoing development throughout the fetal period. Midway through the gestation period, the circular layer was positive for desmin-like immunoreactivity (D-LI), while both the circular and longitudinal layers were positive for vimentin-like immunoreactivity (V-LI). By birth, V-LI was suppressed in the circular and longitudinal layers, and both layers expressed D-LI. The enteric nervous system was already established midway through the gestation period, and submucosal and myenteric ganglia could be identified, although the chemical coding and mature morphology of neurons were incomplete. NADPH-diaphorase-positive neurons, indicating the expression of nitric oxide synthase, developed by the time of birth. Interstitial cells of Cajal (IC) could not clearly be identified midway through gestation, however, potential precursors to ICs were observed. Several classes of ICs were identifiable at birth. Biol Reprod. 1991 Oct ;45 (4):626-33 1751638 Cit:14

Biol Reprod. 1971 Oct;5(2):194-206. The prenatal development of the dog: preimplantation events. Holst PA, Phemister RD.

Prenatal development of purebred beagle dogs was studied from the time of ovulation to the time of implantation. Ovulation occurred 1-2 days after the bitch’s first acceptance of coitus. Primary oocytes were shed from the ovary, and the first evidence of polar body for- mation was observed 3 days after breeding. The embryos entered the uterus as morulae of 16 cells or more, 8-12 days after breeding, and they became blastocysts shortly thereafter. During the free-floating blastocyst stage, which lasted about 1 week, the blastocysts grew to 2.6 mm in diameter and migrated through the uterus. Implantation, first marked by local endometrial edema at the definitive site of each embryo, began an average of 17-18 days after breeding. Shortly after the occurrence of local endometrial edema, differentiation of the primitive streak and three primary germ layers began in the embryo. The age of embryos was assessed on the basis of the time elapsed from breeding, the time elapsed from refusal to breed, and the time after the vaginal smear showed a change from predominantly cornified to predominantly noncornified epithelial cells. The calculated age of embryos at a given stage of development varied as much as 7 days when either postbreeding or postrefusal ages were used. The variation was reduced to 1-2 days when age was deter- mined according to characteristics of the vaginal smear. The early embryonic development in the dog appears to be more closely associated with hormonal events near the end of estrus than with the time of ovulation. The vaginal smear is the bestclinical index of these events.

PMID 5165787

Henry Gray (1825–1861). Anatomy of the Human Body

A series of transverse sections through an embryo of the dog. (After Bonnet.) Section I is the most anterior. In V the neural plate is spread out nearly flat. The series shows the uprising of the neural folds to form the neural canal. a. Aortæ. c. Intermediate cell mass. ect. Ectoderm. ent. Entoderm. h, h. Rudiments of endothelial heart tubes. In III, IV, and V the scattered cells represented between the entoderm and splanchnic layer of mesoderm are the vasoformative cells which give origin in front, according to Bonnet, to the heart tubes, h; l.p. Lateral plate still undivided in I, II, and III; in IV and V split into somatic (sm) and splanchnic (sp) layers of mesoderm. mes. Mesoderm. p. Pericardium. so. Primitive segment.