Platypus Development: Difference between revisions

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Introduction

Platypus, 1840 Cyclopaedia

The platypus (Ornithorhynchus anatinus) also called the "duck-billed platypus" together with the 2 echidna groups (short-beaked and long-beaked) are the only 3 surviving genera of the order Monotremata.

The platypus is a unique egg-laying mammal and is not a common animal model of mammalian embryonic development. It lives in freshwater stream systems and is also the only known mammal that produces venom.

Why platypus? Greek Platus = flat or broad, and pous = foot.

Some Recent Findings

Sex Determination^[1] "One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location."

Mammalian Diversity^[2] "... Monotremes are remarkable because these mammals are born from eggs laid outside of the mother's body. Marsupial mammals have relatively short gestation periods and give birth to highly altricial young that continue a significant amount of "fetal" development after birth, supported by a highly sophisticated lactation. Less than 10% of mammalian species are monotremes or marsupials, so the great majority of mammals are grouped into the subclass Eutheria, including mouse and human."

How did the platypus get its sex chromosome chain? Cite error: Closing </ref> missing for <ref> tag

Five male-specific chromosomes (Y chromosomes) and five chromosomes present in one copy in males and two copies in females (X chromosomes) These ten chromosomes form a multivalent chain at male meiosis, adopting an alternating pattern to segregate into XXXXX-bearing and YYYYY-bearing sperm. .

References

↑ <pubmed>19874722</pubmed>
↑ <pubmed>16478607</pubmed> | CSIRO

Reviews

Hughes RL, Hall LS. [See Related Articles] Early development and embryology of the platypus. Philos Trans R Soc Lond B Biol Sci. 1998 Jul 29;353(1372):1101-14. Review.
Manger PR, Hall LS, Pettigrew JD. [See Related Articles] The development of the external features of the platypus (Ornithorhynchus anatinus). Philos Trans R Soc Lond B Biol Sci. 1998 Jul 29;353(1372):1115-25. Review.
Hughes RL. [See Related Articles] Monotreme development with particular reference to the extraembryonic membranes. J Exp Zool. 1993 Sep 1;266(6):480-94. Review.

Articles

Ashwell KW. [See Related Articles] Cyto- and chemoarchitecture of the monotreme olfactory tubercle. Brain Behav Evol. 2006;67(2):85-102.
Rens W, Grutzner F, O'brien PC, Fairclough H, Graves JA, Ferguson-Smith MA. [See Related Articles] Resolution and evolution of the duck-billed platypus karyotype with an X1Y1X2Y2X3Y3X4Y4X5Y5 male sex chromosome constitution. Proc Natl Acad Sci U S A. 2004 Nov 16;101(46):16257-61.

Books

Platypus: The Extraordinary Story of How a Curious Creature Baffled the World (Hardcover) by Ann Moyal (Amazon Link)
Platypus (Mondo Animals) (Paperback) by Joan Short, Jack Green, Bettina Bird, Andrew Wichlinski (Illustrator) (Amazon Link)

Search PubMed

Search Feb2006 "Platypus development" 303 reference articles of which 5 were reviews.

Search PubMed: Platypus development | monotreme development

External Links

Australian Platypus Conservancy Platypus Fact File | Platypus Historical Background
Access Excellence The National Health Museum (USA) Australian Mammals: Evolutionary Development as a Result of Geographic Isolation
University of Michigan Animal Diversity Web monotremes
University of California, Davis Leah Krubitzer | Krubitzer Lab
University of Texas, Austin Digital Morphology Skull images and movies
NCBI Genome Project Ornithorhynchus anatinus (duck-billed platypus)
BBC Wildfacts Platypus
http://www.platypus.org.uk/

Note: The dynamic nature of the web means that some Links over time change, it the above links no longer function search the web using the first bold term.

Historic Embryology
1897 Pig \| 1900 Chicken \| 1901 Lungfish \| 1904 Sand Lizard \| 1905 Rabbit \| 1906 Deer \| 1907 Tarsiers \| 1908 Human \| 1909 Northern Lapwing \| 1909 South American and African Lungfish \| 1910 Salamander \| 1951 Frog \| Embryology History \| Historic Disclaimer

Glossary Links

Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link

Cite this page: Hill, M.A. (2024, May 18) Embryology Platypus Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Platypus_Development

What Links Here?

[1] <pubmed>19874722</pubmed>

[2] <pubmed>16478607</pubmed> | CSIRO

[1]

[2]

@@ Line 9: / Line 9: @@
 == Some Recent Findings ==
-* Characterisation of ATRX, DMRT1, DMRT7 and WT1 in the platypus (Ornithorhynchus anatinus). Tsend-Ayush E, Lim SL, Pask AJ, Hamdan DD, Renfree MB, Grützner F. Reprod Fertil Dev. 2009;21(8):985-91. [http://www.ncbi.nlm.nih.gov/pubmed/19874722 PMID: 19874722]
+* '''Sex Determination'''<ref><pubmed>19874722</pubmed></ref> "One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location."
-:"One of the most puzzling aspects of monotreme reproductive biology is how they determine sex in the absence of the SRY gene that triggers testis development in most other mammals. Although monotremes share a XX female/XY male sex chromosome system with other mammals, their sex chromosomes show homology to the chicken Z chromosome, including the DMRT1 gene, which is a dosage-dependent sex determination gene in birds. In addition, monotremes feature an extraordinary multiple sex chromosome system. However, no sex determination gene has been identified as yet on any of the five X or five Y chromosomes and there is very little knowledge about the conservation and function of other known genes in the monotreme sex determination and differentiation pathway. We have analysed the expression pattern of four evolutionarily conserved genes that are important at different stages of sexual development in therian mammals. DMRT1 is a conserved sex-determination gene that is upregulated in the male developing gonad in vertebrates, while DMRT7 is a mammal-specific spermatogenesis gene. ATRX, a chromatin remodelling protein, lies on the therian X but there is a testis-expressed Y-copy in marsupials. However, in monotremes, the ATRX orthologue is autosomal. WT1 is an evolutionarily conserved gene essential for early gonadal formation in both sexes and later in testis development. We show that these four genes in the adult platypus have the same expression pattern as in other mammals, suggesting that they have a conserved role in sexual development independent of genomic location."
+* '''Mammalian Diversity'''<ref><pubmed>16478607</pubmed> | [http://www.publish.csiro.au/nid/44/paper/RD05137.htm CSIRO]</ref> "... Monotremes are remarkable because these mammals are born from eggs laid outside of the mother's body. Marsupial mammals have relatively short gestation periods and give birth to highly altricial young that continue a significant amount of "fetal" development after birth, supported by a highly sophisticated lactation. Less than 10% of mammalian species are monotremes or marsupials, so the great majority of mammals are grouped into the subclass Eutheria, including mouse and human."
-* [http://www.publish.csiro.au/nid/44/paper/RD05137.htm Behringer RR, Eakin GS, Renfree MB.] Mammalian Diversity: gametes, embryos and reproduction Reprod. Fertil. Dev. 2006 18, 99-107.
+* '''How did the platypus get its sex chromosome chain?''' <ref><pubmed>16344965</pubmed> "... Its chromosome complement is no less extraordinary, for it includes a system in which ten sex chromosomes form an extensive meiotic chain in males. Such meiotic multiples are unprecedented in vertebrates but occur sporadically in plant and invertebrate species."
-:"... Monotremes are remarkable because these mammals are born from eggs laid outside of the mother's body. Marsupial mammals have relatively short gestation periods and give birth to highly altricial young that continue a significant amount of ‚Äòfetal‚Äô development after birth, supported by a highly sophisticated lactation. Less than 10% of mammalian species are monotremes or marsupials, so the great majority of mammals are grouped into the subclass Eutheria, including mouse and human."
-* [http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16344965&dopt=Abstract Gruetzner F, Ashley T, Rowell DM, Marshall Graves JA.] &nbsp;&nbsp; [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Display&dopt=pubmed_pubmed&from_uid=16344965&tool=ExternalSearch [See Related Articles]] How did the platypus get its sex chromosome chain? A comparison of meiotic multiples and sex chromosomes in plants and animals. Chromosoma. 2005 Dec 13;:1-14
-:"... Its chromosome complement is no less extraordinary, for it includes a system in which ten sex chromosomes form an extensive meiotic chain in males. Such meiotic multiples are unprecedented in vertebrates but occur sporadically in plant and invertebrate species."
 == Taxon ==