SF1 and disorder of sexual differentiation: In our study on XY DSD dogs, we found that the failure of SRY expression due to hypermethylation was well correlated with silencing of SOX9, and therefore also with a serial of testis determining genes, including, SF1, SOX8, AMH and DMRT1, in the early embryonic developmental stage in the XYDSD gonad at E34 (Fig. 4).