提取雄性青鳉成鱼基因组DNA为模板，利用特异性引物，聚合酶链式反应(polymerase chain reaction, PCR)扩增获得1 908 bp的特异性条带.经测序证明为DMY-基因片段，其核苷酸序列由3个外显子和2个内含子组成，可连续编码150个氨基酸.建立准确而有效的鉴定任意发育阶段青鳉个体雌雄性别基因型的方法，即利用管家基因肌动蛋白基因PCR扩增条带的有无验证DNA样本提取和PCR扩增的有效性，同时利用雄性-DMY-基因的PCR扩增条带的有无鉴定青鳉个体的雌雄性别.对随机选取的成鱼和新生鱼卵样本，应用该方法可成功地鉴定出青鳉个体的雌雄性别.

 Genomic DNA was extracted from a male Japanese medaka (Oryzias latipes) and a DNA fragment of 1 908 bp in length was cloned using specific primers by polymerase chain reaction (PCR) amplification. DMY- gene was then identified after sequencing, which consisted of three exons and two introns and encoded a peptide of 150 amino acids. In our study, an accurate and effective method was established for sex identification (gene type) of any development stage of medaka, which is amplifying household βactin gene to testify the DNA template and PCR amplification, and then amplifying specific DMY-gene to distinguish the gender of medaka. The method has been successfully applied to sex identification in randomly selected mature medaka and new born fish eggs. 