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 chromosome. SRY, a gene cloned from the sex-determining region of the human Y chromosome, has been equated with the testis-determining factor in man and mouse. 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 Ube1y homologues, are the first genes to be identified on the marsupial Y chromosome.

Evidence for multiple functional copies of the male sex-determining locus, sry, in African murine rodents

“…There is now considerable evidence that Sry (sex-determining region Y chromosome) is the testis-determining gene (Gubbay et al 1990;Sinclair et al 1990). With rare exception (see, e.g., , Sry is male-specific in all mammal species examined thus far, a sample that includes representatives from three metatherian and seven eutherian orders (Sinclair et al 1990;Foster et al 1992;Pallsboll et al 1992;. It is expressed in the genital ridge at a time consistent with its having a role in testis determination (Gubbay et al 1990;Koopman et al 1991b), and a 14.5-kb mouse genomic DNA fragment containing Sry can induce testis development when injected into (chromosomally female) XX mouse embryos soon after fertilization (Koopman et al 1991a).…”

Embryonic growth and the evolution of the mammalian Y chromosome. II. Suppression of selfish Y-linked growth factors may explain escape from X-inactivation and rapid evolution of Sry

“…Maternal deletions cause excessive suckling whereas paternal deletions cause under-suckling, as would be predicted (Moore & Haig, 1991 (Foster et a!., 1992). Within the HMG box both marsupial genes show extensive homology to human sequence (an average of 67 per cent identity and 84 per cent similarity).…”

Control of sex determination in animals

“…RabbitSRY ERVKRPMNAFMVWSQHQRRQVALENPKMRNSDISKQLGHQWKMLSEAEKWPFFQEAQRLQAMHKEKYPDYKYRPRRKVK (Foster et al, 1992), murine Sry (Gubbay et al, 1990), ovine and bovine SRY (C. Cotinot, unpublished data) and rabbit SRY. Only a portion of the SRY boxes are known in ovine and bovine.…”

“…and two marsupial species Sminthopsis macroura and Macropus eugenii (the Y chromosome is sex-determining in marsupials; Sinclair et al, 1990;Gubbay et al, 1990;Foster et al, 1992 ; C. Cotinot unpublished results). Considerable protein similarity exists between the SRY HMG boxes.…”

“…The gene is located on the mininium portion of the Y chromosome known to confer a male phenotype in both humans and mice (Palmer et al, 1989;Gubbay et al, 1990) and is conserved on the Y chromosome of all eutherian and metatherian mammals tested Foster et al, 1992). SRY is predicted to encode a protein with a DNA binding capacity (see below).…”