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The multiple sex chromosomes of platypus and echidna are not completely identical and several share homology with the avian Z

Rens, Willem; O'Brien, Patricia C M; Grutzner, Frank; Clarke, Oliver; Graphodatskaya, Daria; Tsend-Ayush, Enkhjargal; Trifonov, Vladimir A; Skelton, Helen; Wallis, Mary C; Johnston, Steve; Veyrunes, Frederic; Graves, Jennifer AM; Ferguson-Smith, Malcolm A

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BACKGROUND Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has...[Show more]

dc.contributor.authorRens, Willem
dc.contributor.authorO'Brien, Patricia C M
dc.contributor.authorGrutzner, Frank
dc.contributor.authorClarke, Oliver
dc.contributor.authorGraphodatskaya, Daria
dc.contributor.authorTsend-Ayush, Enkhjargal
dc.contributor.authorTrifonov, Vladimir A
dc.contributor.authorSkelton, Helen
dc.contributor.authorWallis, Mary C
dc.contributor.authorJohnston, Steve
dc.contributor.authorVeyrunes, Frederic
dc.contributor.authorGraves, Jennifer AM
dc.contributor.authorFerguson-Smith, Malcolm A
dc.date.accessioned2015-09-04T04:58:45Z
dc.date.available2015-09-04T04:58:45Z
dc.identifier.issn1465-6906
dc.identifier.urihttp://hdl.handle.net/1885/15207
dc.description.abstractBACKGROUND Sex-determining systems have evolved independently in vertebrates. Placental mammals and marsupials have an XY system, birds have a ZW system. Reptiles and amphibians have different systems, including temperature-dependent sex determination, and XY and ZW systems that differ in origin from birds and placental mammals. Monotremes diverged early in mammalian evolution, just after the mammalian clade diverged from the sauropsid clade. Our previous studies showed that male platypus has five X and five Y chromosomes, no SRY, and DMRT1 on an X chromosome. In order to investigate monotreme sex chromosome evolution, we performed a comparative study of platypus and echidna by chromosome painting and comparative gene mapping. RESULTS Chromosome painting reveals a meiotic chain of nine sex chromosomes in the male echidna and establishes their order in the chain. Two of those differ from those in the platypus, three of the platypus sex chromosomes differ from those of the echidna and the order of several chromosomes is rearranged. Comparative gene mapping shows that, in addition to bird autosome regions, regions of bird Z chromosomes are homologous to regions in four platypus X chromosomes, that is, X1, X2, X3, X5, and in chromosome Y1. CONCLUSION Monotreme sex chromosomes are easiest to explain on the hypothesis that autosomes were added sequentially to the translocation chain, with the final additions after platypus and echidna divergence. Genome sequencing and contig anchoring show no homology yet between platypus and therian Xs; thus, monotremes have a unique XY sex chromosome system that shares some homology with the avian Z.
dc.description.sponsorshipThis work was performed at the Cambridge Resource Centre for Comparative Genomics at the University of Cambridge, which is supported by a generous grant from the Wellcome Trust to MAFS and WR (grant no. 077121). The Australian Research Council supports FG and JAMG.
dc.publisherBioMed Central
dc.rightsCopyright © 2007 Rens et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.sourceGenome Biology
dc.subjectanimals
dc.subjectbirds
dc.subjectchromosome painting
dc.subjectchromosomes, artificial, bacterial
dc.subjectechidna
dc.subjectfemale
dc.subjecthumans
dc.subjectkaryotyping
dc.subjectmale
dc.subjectmicroscopy, fluorescence
dc.subjectplatypus
dc.subjectpolymerase chain reaction
dc.subjectsex chromosomes
dc.titleThe multiple sex chromosomes of platypus and echidna are not completely identical and several share homology with the avian Z
dc.typeJournal article
local.identifier.citationvolume8
dc.date.issued2007
local.identifier.absfor060407 - Genome Structure and Regulation
local.identifier.ariespublicationu9204316xPUB370
local.type.statusPublished Version
local.contributor.affiliationGraves, Jennifer A M, Research School of Biological Sciences, The Australian National University
local.identifier.essn1474-760X
local.bibliographicCitation.issue11
local.bibliographicCitation.startpageR243
local.bibliographicCitation.lastpage44
local.identifier.doi10.1186/gb-2007-8-11-r243
dc.date.updated2016-02-24T11:52:10Z
local.identifier.scopusID2-s2.0-43249121975
CollectionsANU Research Publications

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