File:Mouse sex determination genes 01.jpg

Overview of sex determination in mice

During mouse embryogenesis, bipotential gonads arise from the genital ridges by 10.5 days post-conception (dpc).

In somatic cells of XY genital ridges, Sry expression (dark blue line at lower part of figure) starts at 10.5 dpc, reaches a peak at 11.5 dpc and then wanes by 12.5 dpc. A few hours later, Sox9 expression (light blue line at the lower part of the figure) is upregulated to induce di erentiation of Sertoli cells. Sox9 expression peaks at 11.5 to 12.5 dpc, continues to be expressed postnatally and is supported by several positive-feedback loops (including broblast growth factor 9 (FGF9), prostaglandin D2 (PGD2) and SOX9 itself ), and SOX9 subsequently activates many male-speci c genes, including the gene encoding anti-Müllerian hormone (Amh). At 12.5 dpc, morphological di erences between testis and ovary are evident. In the absence of SRY, genes such as Wnt4, Rspo1 and Foxl2 are expressed in a female-speci c manner and induce ovarian development, as characterized by the expression of follistatin and many other ovary-speci c genes. FOXL2, forkhead box L2; SOX9, SRY box containing gene 9; SRY, sex-determining region on the chromosome Y.

Reference

de Lau WB, Snel B & Clevers HC. (2012). The R-spondin protein family. Genome Biol. , 13, 242. PMID: 22439850 DOI.

Kashimada K & Koopman P. (2010). Sry: the master switch in mammalian sex determination. Development , 137, 3921-30. PMID: 21062860 DOI.