Talk:Platypus Development - Revision history

Z8600021 at 02:05, 30 April 2020

2020-04-30T02:05:52Z

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	{{Ref-Smith1899}}		{{Ref-Smith1899}}

	==~~10 Most Recent Papers~~==		==2018==
	~~{{10 Most Recent}}~~

	~~===Platypus Development===~~		{{#pmid:29688544}}
	~~<pubmed limit=5>Platypus Development</pubmed>~~

	~~===~~Platypus ~~Embryology===~~		'''Insights into Platypus Population Structure and History from Whole-Genome Sequencing
	~~<pubmed limit=5>Platypus Embryology<~~/~~pubmed>~~		'''
			The platypus is an egg-laying mammal which, alongside the echidna, occupies a unique place in the mammalian phylogenetic tree. Despite widespread interest in its unusual biology, little is known about its population structure or recent evolutionary history. To provide new insights into the dispersal and demographic history of this iconic species, we sequenced the genomes of 57 platypuses from across the whole species range in eastern mainland Australia and Tasmania. Using a highly improved reference genome, we called over 6.7 M SNPs, providing an informative genetic data set for population analyses. Our results show very strong population structure in the platypus, with our sampling locations corresponding to discrete groupings between which there is no evidence for recent gene flow. Genome-wide data allowed us to establish that 28 of the 57 sampled individuals had at least a third-degree relative among other samples from the same river, often taken at different times. Taking advantage of a sampled family quartet, we estimated the de novo mutation rate in the platypus at 7.0 × 10-9/bp/generation (95% CI 4.1 × 10-9-1.2 × 10-8/bp/generation). We estimated effective population sizes of ancestral populations and haplotype sharing between current groupings, and found evidence for bottlenecks and long-term population decline in multiple regions, and early divergence between populations in different regions. This study demonstrates the power of whole-genome sequencing for studying natural populations of an evolutionarily important species.
			PMID: 29688544 PMCID: PMC5913675 DOI: 10.1093/molbev/msy041

	==2013==		==2013==

Z8600021 at 08:21, 1 October 2018

2018-10-01T08:21:40Z

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			{{Ref-Smith1899}}

	==10 Most Recent Papers==		==10 Most Recent Papers==

Z8600021 at 07:21, 22 October 2014

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	==Historic==		==Historic==

	* The Cochlea of the Ornithorhynchus platypus Compared with That of Ordinary Mammals and of Birds. Pritchard, U Proceedings of the Royal Society of London (1854-1905). (January 1, 1880) 31:149–153 https://archive.org/details/philtrans01788712		* [[1880 - Platypus Cochlea Compared with Mammals and Birds\|The Cochlea of the Ornithorhynchus platypus Compared with That of Ordinary Mammals and of Birds]] Pritchard, U Proceedings of the Royal Society of London (1854-1905). (January 1, 1880) 31:149–153 https://archive.org/details/philtrans01788712
	* Some Remarks on the Internal Structure of the Platypus Anatinus (Ornithorhyncus paradoxus, Blum.) (January 1, 1830) https://archive.org/details/philtrans01902270		* Some Remarks on the Internal Structure of the Platypus Anatinus (Ornithorhyncus paradoxus, Blum.) (January 1, 1830) https://archive.org/details/philtrans01902270

Z8600021 at 07:12, 22 October 2014

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	==Historic==		==Historic==
	* The Cochlea of the Ornithorhynchus platypus Compared with That of Ordinary Mammals and of Birds. (January 1, 1880) https://archive.org/details/philtrans01788712
			* The Cochlea of the Ornithorhynchus platypus Compared with That of Ordinary Mammals and of Birds. Pritchard, U Proceedings of the Royal Society of London (1854-1905). (January 1, 1880) 31:149–153 https://archive.org/details/philtrans01788712
	* Some Remarks on the Internal Structure of the Platypus Anatinus (Ornithorhyncus paradoxus, Blum.) (January 1, 1830) https://archive.org/details/philtrans01902270		* Some Remarks on the Internal Structure of the Platypus Anatinus (Ornithorhyncus paradoxus, Blum.) (January 1, 1830) https://archive.org/details/philtrans01902270

Z8600021 at 10:16, 1 November 2013

2013-11-01T10:16:13Z

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	Cartilage canals are present in the epiphyseal cartilage of most mammals and birds. They are considered necessary for the maintenance of chondrocytes and for the formation of epiphyseal ossification centers. The epiphyseal cartilage of marsupials was recently shown not to contain cartilage canals, and placental rats appear not to have cartilage canals, although some confusion exists in the literature. The present study examines the cartilaginous epiphyses and physes from the knee and hip of the rat and the two Australian monotremes (platypus, Ornithorhynchus anatinus and echidna, Tachyglossus aculeatus). In all three species, cartilage canals were absent. Vessels to epiphyseal ossification centers were present, however. In the center of the cartilaginous femoral head of the echidna, but not in the platypus or rat, there was a large cavity, which contained connective tissue and was lined by an endochondrium of chondroproginator cells. These appeared to be contributing to growth of the cartilaginous epiphysis. No similar structure has previously been described in the cartilaginous epiphysis of other species. There was no ligament of the femoral head in the hip joints of the monotremes, and it is suggested the absence of a ligament may be significant in the development of the cavity. It was noted in all specimens that despite being avascular the epiphyseal and physeal cartilage appeared viable and functionally normal. The small size of the cartilaginous epiphyses of the rat may account for their avascularity; but the epiphyses of the monotremes were much larger, especially the echidna, yet still avascular. These features provide strong evidence for fundamental differences between the avascular cartilage of monotremes and the vascular cartilage of most mammals.		Cartilage canals are present in the epiphyseal cartilage of most mammals and birds. They are considered necessary for the maintenance of chondrocytes and for the formation of epiphyseal ossification centers. The epiphyseal cartilage of marsupials was recently shown not to contain cartilage canals, and placental rats appear not to have cartilage canals, although some confusion exists in the literature. The present study examines the cartilaginous epiphyses and physes from the knee and hip of the rat and the two Australian monotremes (platypus, Ornithorhynchus anatinus and echidna, Tachyglossus aculeatus). In all three species, cartilage canals were absent. Vessels to epiphyseal ossification centers were present, however. In the center of the cartilaginous femoral head of the echidna, but not in the platypus or rat, there was a large cavity, which contained connective tissue and was lined by an endochondrium of chondroproginator cells. These appeared to be contributing to growth of the cartilaginous epiphysis. No similar structure has previously been described in the cartilaginous epiphysis of other species. There was no ligament of the femoral head in the hip joints of the monotremes, and it is suggested the absence of a ligament may be significant in the development of the cavity. It was noted in all specimens that despite being avascular the epiphyseal and physeal cartilage appeared viable and functionally normal. The small size of the cartilaginous epiphyses of the rat may account for their avascularity; but the epiphyses of the monotremes were much larger, especially the echidna, yet still avascular. These features provide strong evidence for fundamental differences between the avascular cartilage of monotremes and the vascular cartilage of most mammals.

	PMID: ~~2048749~~		PMID 2048749

			==Historic==
			* The Cochlea of the Ornithorhynchus platypus Compared with That of Ordinary Mammals and of Birds. (January 1, 1880) https://archive.org/details/philtrans01788712
			* Some Remarks on the Internal Structure of the Platypus Anatinus (Ornithorhyncus paradoxus, Blum.) (January 1, 1830) https://archive.org/details/philtrans01902270

Z8600021 at 15:03, 5 August 2013

2013-08-05T15:03:43Z

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	==2013==		==2013==

			===Identification and functional characterization of a novel monotreme- specific antibacterial protein expressed during lactation===

			PLoS One. 2013;8(1):e53686. doi: 10.1371/journal.pone.0053686. Epub 2013 Jan 9.

			Bisana S, Kumar S, Rismiller P, Nicol SC, Lefèvre C, Nicholas KR, Sharp JA.

			Source
			Centre for Chemistry and Biotechnology, Deakin University, Geelong, Victoria, Australia. swathib@ccmb.res.in

			Abstract

			Monotremes are the only oviparous mammals and exhibit a fascinating combination of reptilian and mammalian characters. They represent a component of synapsidal reproduction by laying shelled eggs which are incubated outside the mother's body. This is accompanied by a prototherian lactation process, marking them as representatives of early mammals. The only extant monotremes are the platypus, and the short- and long- beaked echidnas, and their distributions are limited to Australia and New Guinea. Apart for a short weaning period, milk is the sole source of nutrition and protection for the hatchlings which are altricial and immunologically naive. The duration of lactation in these mammals is prolonged relative to the gestational length and period of incubation of eggs. Much of the development of monotreme young occurs in the non-sterile ex-utero environment. Therefore the role of milk in the growth, development and disease protection of the young is of significant interest. By sequencing the cDNA of cells harvested from monotreme milk, we have identified a novel monotreme- specific transcript, and the corresponding gene was designated as the EchAMP. The expression profile of this gene in various tissues revealed that it is highly expressed in milk cells. The peptides corresponding to the EchAMP protein have been identified in a sample of echidna milk In silico analysis indicated putative antimicrobial potential for the cognate protein of EchAMP. This was further confirmed by in vitro assays using a host of bacteria. Interestingly, EchAMP did not display any activity against a commensal gut floral species. These results support the hypothesis of enhancement of survival of the young by antimicrobial bioactives of mammary gland origin and thus emphasize the protective, non- nutritional role of milk in mammals.

			PMID 23326486

	==2012==		==2012==

Z8600021 at 20:38, 24 December 2012

2012-12-24T20:38:07Z

← Older revision		Revision as of 06:38, 25 December 2012
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	{{Talk Page}}		{{Talk Page}}

			==10 Most Recent Papers==
			{{10 Most Recent}}

			===Platypus Development===
			<pubmed limit=5>Platypus Development</pubmed>

			===Platypus Embryology===
			<pubmed limit=5>Platypus Embryology</pubmed>

			==2013==


	==2012==		==2012==

Z8600021 at 08:04, 23 August 2012

2012-08-23T08:04:14Z

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	==2012==		==2012==

			===Development of the cerebellum in the platypus (Ornithorhynchus anatinus) and short-beaked echidna (Tachyglossus aculeatus)===
			Brain Behav Evol. 2012;79(4):237-51. Epub 2012 May 3.

			Ashwell KW.
			Source
			Department of Anatomy, School of Medical Sciences, The University of New South Wales, Sydney, Australia.

			Abstract

			The monotremes are a unique group of mammals whose young are incubated in a leathery-shelled egg and fed with milk from teatless areolae after hatching. As soon as they hatch, monotreme young must be able to maneuver around the nest or maternal pouch to locate the areolae and stimulate milk ejection. In the present study, the embryological collections at the Museum für Naturkunde, Berlin, have been used to follow the development of the monotreme cerebellum through incubation and lactational phases, to determine whether cerebellar circuitry is able to contribute to the coordination of locomotion in the monotreme hatchling, and to correlate cerebellar development with behavioral maturation. The structure of the developing monotreme cerebellum and the arrangement of transitory neuronal populations are similar to those reported for fetal and neonatal eutherians, but the time course of the key events of later cerebellar development is spread over a much longer period. Expansion of the rostral rhombic lip and formation of the nuclear and cortical transitory zones occurs by the time of hatching, but it is not until after the end of the first post-hatching week that deep cerebellar neurons begin to settle in their definitive positions and the Purkinje cell layer can be distinguished. Granule cell formation is also prolonged over many post-hatching months and the external granular layer persists for more than 20 weeks after hatching. The findings indicate that cerebellar circuitry is unlikely to contribute to the coordination of movements in the monotreme peri-hatching period. Those activities are most likely controlled by the spinal cord and medullary reticular formation circuitry.
			Copyright © 2012 S. Karger AG, Basel.

			PMID 22572119

	===Distinct development of the cerebral cortex in platypus and echidna===		===Distinct development of the cerebral cortex in platypus and echidna===

Z8600021 at 08:02, 23 August 2012

2012-08-23T08:02:46Z

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 {{Talk Page}}
 ==2011==
 ===Monotreme ossification sequences and the riddle of Mammalian skeletal development===

S8600021: /* 2003 */

2011-05-05T22:06:36Z

2003

← Older revision		Revision as of 08:06, 6 Mayıs 2011
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	PMID: 14667846		PMID: 14667846
	http://www.ncbi.nlm.nih.gov/pubmed/14667846		http://www.ncbi.nlm.nih.gov/pubmed/14667846

			==1991==
			===Cartilaginous bone extremities of growing monotremes appear unique===
			Anat Rec. 1991 Apr;229(4):447-52.

			Thorp BH, Dixon JM.
			Source
			Department of Veterinary Preclinical Science, University of Melbourne, Parkville, Victoria, Australia.

			Abstract

			Cartilage canals are present in the epiphyseal cartilage of most mammals and birds. They are considered necessary for the maintenance of chondrocytes and for the formation of epiphyseal ossification centers. The epiphyseal cartilage of marsupials was recently shown not to contain cartilage canals, and placental rats appear not to have cartilage canals, although some confusion exists in the literature. The present study examines the cartilaginous epiphyses and physes from the knee and hip of the rat and the two Australian monotremes (platypus, Ornithorhynchus anatinus and echidna, Tachyglossus aculeatus). In all three species, cartilage canals were absent. Vessels to epiphyseal ossification centers were present, however. In the center of the cartilaginous femoral head of the echidna, but not in the platypus or rat, there was a large cavity, which contained connective tissue and was lined by an endochondrium of chondroproginator cells. These appeared to be contributing to growth of the cartilaginous epiphysis. No similar structure has previously been described in the cartilaginous epiphysis of other species. There was no ligament of the femoral head in the hip joints of the monotremes, and it is suggested the absence of a ligament may be significant in the development of the cavity. It was noted in all specimens that despite being avascular the epiphyseal and physeal cartilage appeared viable and functionally normal. The small size of the cartilaginous epiphyses of the rat may account for their avascularity; but the epiphyses of the monotremes were much larger, especially the echidna, yet still avascular. These features provide strong evidence for fundamental differences between the avascular cartilage of monotremes and the vascular cartilage of most mammals.

			PMID: 2048749