Sex determination in mammals. How many genes are involved?
The genetic mechanisms of sex determination in mammals have not yet been clarified. Y-linked and X-linked zinc finger genes from humans and mice were recently cloned and characterized. The Y-linked zinc finger gene was originally thought to be the testis-determining factor. However, at the present time, it seems clear that this gene is not the master gene triggering the cascade of events leading to sex determination. The human testis-determining factor gene is known to be located in the nonhomologous region of the short arm of the Y chromosome, close to an Alu repeat that marks the boundary of the pseudoautosomal region. Lately, this region has been found to contain a new gene that is a strong candidate for the male-determining factor. Data on humans and on laboratory and vole mice showing abnormalities of the sex determination mechanisms indicate that testis development depends on the presence of a testis-determining factor gene functioning in cooperation with X-linked and autosomal genes. Ovary development would depend on the absence of the testis-determining factor and perhaps on an alternative splicing of the transcripts from autosomal and X-linked genes involved in sex determination.
Bianchi
N O
NO
IMBICE, La Plata, Argentina.
D000818:Animals; D003411:Arvicolinae; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D012732:Sex Determination Analysis; D014960:X Chromosome; D014998:Y Chromosome; D016335:Zinc Fingers / Q000235:genetics