Evolution of sex determination and the Y chromosome: SRY-related sequences in marsupials

Abstract

In mammals, testis determination is under the control of the testis-determining factor borne by the Y chromosome1,2. SRY, a gene cloned from the sex-determining region of the human Y chromosome, has been equated with the testis-determining factor in man3-5 and mouse 6,7. We have used a human SRY probe to identify and clone related genes from the Y chromosome of two marsupial species. Comparisons of eutherian and metatherian Y-located SRY sequences suggest rapid evolution of these genes, especially outside the region encoding the DNA-binding HMG box. The SRY homologues, together with the mouse Ubely homologues8, are the first genes to be identified on the marsupial Y chromosome. © 1992 Nature..