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Hens, cocks and avian sex determination
Author(s) -
Ellegren Hans
Publication year - 2001
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kve050
Subject(s) - biology , w chromosome , genetics , caenorhabditis elegans , gene , sexual differentiation , drosophila melanogaster , x chromosome , chromosome , sex linkage , y chromosome , dosage compensation , melanogaster , evolutionary biology , karyotype
The sex of an individual is generally determined genetically by genes on one of the two sex chromosomes. In mammals, for instance, the presence of the male‐specific Y chromosome confers maleness, whereas in Drosophila melanogaster and Caenorhabditis elegans it is the number of X chromosomes that matters. For birds (males ZZ, females ZW), however, the situation remains unclear. The recent discovery that the Z‐linked DMRT1 gene, which is conserved across phyla as a gene involved in sexual differentiation, is expressed early in male development suggests that it might be the number of Z chromosomes that regulate sex in birds. On the other hand, the recent identification of the first protein unique to female birds, encoded by the W‐linked PKCIW gene, and the observation that it is expressed early in female gonads, suggests that the W chromosome plays a role in avian sexual differentiation. Clearly defining the roles of the DMRT1 and PKC1W genes in gonadal development, and ultimately determining whether avian sex is dependent on Z or W, will require transgenic experiments.