title: Anatomical and molecular analyses of XY ovaries from the African pygmy mouse Mus minutoides.
abstract: The African pygmy mouse Mus minutoides is characterized by the presence of a high proportion of fertile XY females in natural populations. This species displays 2 morphologically different X chromosomes: the ancestral X and a shorter one designated as X*, feminizing the X*Y individuals. This strongly suggests that in the presence of an X* chromosome, the male differentiation program is not activated despite a functional Y chromosome. In this study, we compared the histology of the adult ovaries of the 3 female genotypes (XX, XX* and X*Y) and investigated the expression of some of the main genes involved in male and female differentiation. We found that X*Y gonads display a typical ovarian structure without any testicular organization. Moreover, the ovarian somatic marker FOXL2 is detected in X*Y follicle cells and exhibits the same pattern as in XX and XX* ovaries, whereas SOX9 and DMRT1 are absent at all stages of follicular differentiation. However, surprisingly, X*Y ovaries display a higher level of Sry transcripts compared to testes. Our findings confirm the complete sex reversal in X*Y individuals with no apparent sign of masculinization, providing an attractive model to unravel new gene interactions involved in the mammalian sex determination system.
authors.affiliation: Institut des Sciences de l'Evolution de Montpellier, Université Montpellier 2, CNRS, IRD, Montpellier, France.
authors.forename: Massilva
authors.initials: M
authors.lastname: Rahmoun
authors.forename: Julie
authors.initials: J
authors.lastname: Perez
authors.forename: Paul A
authors.initials: PA
authors.lastname: Saunders
authors.forename: Brigitte
authors.initials: B
authors.lastname: Boizet-Bonhoure
authors.forename: Dagmar
authors.initials: D
authors.lastname: Wilhelm
authors.forename: Francis
authors.initials: F
authors.lastname: Poulat
authors.forename: Frédéric
authors.initials: F
authors.lastname: Veyrunes
mesh_terms: D000349:Africa; D000818:Animals; D001835:Body Weight; D033481:Chromosomes, Mammalian / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D010053:Ovary / Q000033:anatomy & histology* / Q000378:metabolism*; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019849:Sex Determination Processes / Q000235:genetics*; D051876:Sex-Determining Region Y Protein / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D014960:X Chromosome / Q000235:genetics*; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D051876:Sex-Determining Region Y Protein