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). This evidence concerns the gene SOX9 and disorder of sexual differentiation.