Abstract:The Dmrt4 gene was cloned from the ovary of Megalobrama amblycephala via using rapid amplification of cDNA ends (RACE) PCR.The relative expression of Dmrt4 gene at different stages of embryonic and post-embryonic development,in different adult tissues,and at different stages of gonad in M.amblycephala were analyzed by quantitative real-time PCR.The results showed that the Dmrt4 gene in M.amblycephala contains at least two isoforms named Dmrt4a and Dmrt4b,respectively.The cDNA of Dmrt4a was 1 265 bp encoding 352 amino acids containing DM and DMA domains,and the cDNA of Dmrt4b was 1 081 bp encoding 281 amino acids containing DMA domain.The amino acids sequences of Dmrt4 genes in M.amblycephala had high identities with that of Paralichthys olivaceus and Oreochromis aureus.The Dmrt4 gene was expressed from embryo to 30 dph (day post hatching) continuously and reached the peak at 32 hpf (hour post fertilization),the gene expression in ovary was significantly (P<0.01) higher than in other adult tissues,and the gene expression at Stage Ⅱ of the ovary was significantly (P<0.01) higher than that of other ovary stages and the testis stages,suggesting that the Dmrt4 gene may play a vital role in primary oocytes and female gonad development in M.amblycephala.