Talk:Platypus Development
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Cite this page: Hill, M.A. (2024, May 3) Embryology Platypus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Platypus_Development |
2011
Monotreme ossification sequences and the riddle of Mammalian skeletal development
Evolution. 2011 May;65(5):1323-35. doi: 10.1111/j.1558-5646.2011.01234.x. Epub 2011 Feb 18.
Weisbecker V. Source Earth Sciences, University of Cambridge, Downing St. CB2 3EQ, Cambridge, United Kingdom Institut für Spezielle Zoologie und Evolutionsbiologie, Friedrich-Schiller Universität Jena, Erbertstr.1, 07743 Jena, Germany E-mail: vw248@cam.ac.uk.
Abstract
The developmental differences between marsupials, placentals, and monotremes are thought to be reflected in differing patterns of postcranial development and diversity. However, developmental polarities remain obscured by the rarity of monotreme data. Here, I present the first postcranial ossification sequences of the monotreme echidna and platypus, and compare these with published data from other mammals and amniotes. Strikingly, monotreme stylopodia (humerus, femur) ossify after the more distal zeugopodia (radius/ulna, tibia/fibula), resembling only the European mole among all amniotes assessed. European moles also share extreme humeral adaptations to rotation digging and/or swimming with monotremes, suggesting a causal relationship between adaptation and ossification heterochrony. Late femoral ossification with respect to tibia/fibula in monotremes and moles points toward developmental integration of the serially homologous fore- and hindlimb bones. Monotreme cervical ribs and coracoids ossify later than in most amniotes but are similarly timed as homologous ossifications in therians, where they are lost as independent bones. This loss may have been facilitated by a developmental delay of coracoids and cervical ribs at the base of mammals. The monotreme sequence, although highly derived, resembles placentals more than marsupials. Thus, marsupial postcranial development, and potentially related diversity constraints, may not represent the ancestral mammalian condition.
© 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.
PMID: 21521190
2010
Early development and embryology of the platypus
Hughes RL, Hall LS. Philos Trans R Soc Lond B Biol Sci. 1998 Jul 29;353(1372):1101-14. Review. PMID: 9720108
Cereb Cortex. 2010 May;20(5):1071-81. Epub 2009 Sep 2.
The subventricular zone is the developmental milestone of a 6-layered neocortex: comparisons in metatherian and eutherian mammals.
Cheung AF, Kondo S, Abdel-Mannan O, Chodroff RA, Sirey TM, Bluy LE, Webber N, DeProto J, Karlen SJ, Krubitzer L, Stolp HB, Saunders NR, Molnár Z.
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK. Abstract The major lineages of mammals (Eutheria, Metatheria, and Monotremata) diverged more than 100 million years ago and have undergone independent changes in the neocortex. We found that adult South American gray short-tailed opossum (Monodelphis domestica) and tammar wallaby (Macropus eugenii) possess a significantly lower number of cerebral cortical neurons compared with the mouse (Mus musculus). To determine whether the difference is reflected in the development of the cortical germinal zones, the location of progenitor cell divisions was examined in opossum, tammar wallaby, and rat. The basic pattern of the cell divisions was conserved, but the emergence of a distinctive band of dividing cells in the subventricular zone (SVZ) occurred relatively later in the opossum (postnatal day [P14]) and the tammar wallaby (P40) than in rodents. The planes of cell divisions in the ventricular zone (VZ) were similar in all species, with comparable mRNA expression patterns of Brn2, Cux2, NeuroD6, Tbr2, and Pax6 in opossum (P12 and P20) and mouse (embryonic day 15 and P0). In conclusion, the marsupial neurodevelopmental program utilizes an organized SVZ, as indicated by the presence of intermediate (or basal) progenitor cell divisions and gene expression patterns, suggesting that the SVZ emerged prior to the Eutherian-Metatherian split.
PMID: 19726493
Evolution of lactation: ancient origin and extreme adaptations of the lactation system
Annu Rev Genomics Hum Genet. 2010 Sep 22;11:219-38.
Lefèvre CM, Sharp JA, Nicholas KR. Source Institute for Technology Research and Innovation, Deakin University, Waurn Ponds, VIC 3217, Australia. clefevre@deakin.edu.au
Abstract
Lactation, an important characteristic of mammalian reproduction, has evolved by exploiting a diversity of strategies across mammals. Comparative genomics and transcriptomics experiments have now allowed a more in-depth analysis of the molecular evolution of lactation. Milk cell and mammary gland genomic studies have started to reveal conserved milk proteins and other components of the lactation system of monotreme, marsupial, and eutherian lineages. These analyses confirm the ancient origin of the lactation system and provide useful insight into the function of specific milk proteins in the control of lactation. These studies also illuminate the role of milk in the regulation of growth and development of the young beyond simple nutritive aspects.
PMID: 20565255 http://www.ncbi.nlm.nih.gov/pubmed/20565255
http://www.annualreviews.org/doi/abs/10.1146/annurev-genom-082509-141806
Phylogenetic origins of early alterations in brain region proportions
Brain Behav Evol. 2010;75(2):104-10. Epub 2010 Mar 23.
Charvet CJ, Sandoval AL, Striedter GF. Source Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, Calif. 92687-4550, USA. ccharvet@uci.edu
Abstract
Adult galliform birds (e.g. chickens) exhibit a relatively small telencephalon and a proportionately large optic tectum compared with parrots and songbirds. We previously examined the embryonic origins of these adult species differences and found that the optic tectum is larger in quail than in parakeets and songbirds at early stages of development, prior to tectal neurogenesis onset. The aim of this study was to determine whether a proportionately large presumptive tectum is a primitive condition within birds or a derived feature of quail and other galliform birds. To this end, we examined embryonic brains of several avian species (emus, parrots, songbirds, waterfowl, galliform birds), reptiles (3 lizard species, alligators, turtles) and a monotreme (platypuses). Brain region volumes were estimated from serial Nissl-stained sections. We found that the embryos of galliform birds and lizards exhibit a proportionally larger presumptive tectum than all the other examined species. The presumptive tectum of the platypus is unusually small. The most parsimonious interpretation of these data is that the expanded embryonic tectum of lizards and galliform birds is a derived feature in both of these taxonomic groups.
Copyright 2010 S. Karger AG, Basel.
PMID: 20332607 http://www.ncbi.nlm.nih.gov/pubmed/20332607
http://content.karger.com/produktedb/produkte.asp?DOI=000300573&typ=pdf
