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#116908 - 11/09/17 04:00 PM Re: Journal papers online - reference list [Re: KazJaps]
Wieslaw Offline
Classroom Professor

Registered: 09/18/09
Posts: 3757
Loc: Denmark
Sex Reversal and Comparative Data Undermine the W Chromosome and Support Z-linked DMRT1 as the Regulator of Gonadal Sex Differentiation in Birds.


The exact genetic mechanism regulating avian gonadal sex differentiation has not been completely resolved. The most likely scenario involves a dosage mechanism, whereby the Z-linked DMRT1 gene triggers testis development. However, the possibility still exists that the female-specific W chromosome may harbor an ovarian determining factor. In this study, we provide evidence that the universal gene regulating gonadal sex differentiation in birds is Z-linked DMRT1 and not a W-linked (ovarian) factor. Three candidate W-linked ovarian determinants are HINTW, female-expressed transcript 1 (FET1), and female-associated factor (FAF). To test the association of these genes with ovarian differentiation in the chicken, we examined their expression following experimentally induced female-to-male sex reversal using the aromatase inhibitor fadrozole (FAD). Administration of FAD on day 3 of embryogenesis induced a significant loss of aromatase enzyme activity in female gonads and masculinization. However, expression levels of HINTW, FAF, and FET1 were unaltered after experimental masculinization. Furthermore, comparative analysis showed that FAF and FET1 expression could not be detected in zebra finch gonads. Additionally, an antibody raised against the predicted HINTW protein failed to detect it endogenously. These data do not support a universal role for these genes or for the W sex chromosome in ovarian development in birds. We found that DMRT1 (but not the recently identified Z-linked HEMGN gene) is male upregulated in embryonic zebra finch and emu gonads, as in the chicken. As chicken, zebra finch, and emu exemplify the major evolutionary clades of birds, we propose that Z-linked DMRT1, and not the W sex chromosome, regulates gonadal sex differentiation in birds.

#116919 - 11/21/17 12:30 AM Re: Journal papers online - reference list [Re: KazJaps]
Redcap Online   content
Ruler of the Roost

Registered: 08/14/06
Posts: 952
Loc: Germany
Kimball, E. (1953). Genetics of Buttercup Plumage Pattern in the Fowl, Poultry Science, Volume 32, Issue 4, 1 July 1953, Pages 683692.
Kimball, E. (1960). Differential Penciled Phenotypes & Genetic Origin of Penciled Pattern. Volume 39, Issue 1, 1 January 1960, Pages 232-234.

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