Proposed role of w chromosome inactivation and the absence of dosage compensation in avian sex determination
Data(s) |
22/10/1994
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Resumo |
Three features of avian sex chromosomes - female heterogamety (ZZ male, ZW female), the apparently inactive state of the W chromosome, and dose-dependent expression of Z-linked genes - are examined in regard to their possible relation to sex determination. It is proposed that the W chromosome is facultatively heterochromatic and that the Z and W chromosomes carry one or more homologous sex-determination genes. The absence of dosage compensation in ZZ embryos, and W inactivation in ZW embryos, would then bring about a 2n(ZZ)-n(ZW) inequality in the effective copy number of such genes. The absence of dosage compensation of Z-linked genes in ZZ embryos is viewed as a means by which two copies of Z-W homologous sex determination genes are kept active to meet the requirements of testis determination. W inactivation may promote ovarian development by reducing the effective copy number of these genes from 2n to n. If there is a W-specific gene for femaleness, spread of heterochromatization to this gene in cells forming the right gonadal primordium may explain the latter's normally undifferentiated state; reversal of heterochromatization may similarly explain the development of the right gonad into a testis following left ovariectomy. |
Formato |
application/pdf |
Identificador |
http://eprints.iisc.ernet.in/36709/1/proposed_role_of_w.pdf Chandra, Sharat H (1994) Proposed role of w chromosome inactivation and the absence of dosage compensation in avian sex determination. In: Proceedings of the Royal Society B: Biological Sciences, 258 (1351). pp. 79-82. |
Publicador |
The royal society |
Relação |
http://rspb.royalsocietypublishing.org/content/258/1351/79 http://eprints.iisc.ernet.in/36709/ |
Palavras-Chave | #Microbiology & Cell Biology |
Tipo |
Journal Article PeerReviewed |