Identification of a male-specific DNA marker in the large yellow croaker (Larimichthys crocea)

Understanding sex determination mechanisms is the first and most paramount step in the development of sex control breeding biotechnologies for fish. The large yellow croaker (Larimichthys crocea) is an economically vital fish in China and East Asia, which exhibits a sex-related growth dimorphism where females grow significantly faster than males. However, the lack of a rapid and accurate sex specific marker for the large yellow croaker has hampered the application of sex control in the breeding process, as well as sex-determination investigations of this species. In this study, a male-specific 15 bp deletion in the third intron of the Dmrt1 gene was identified by comparative analysis of genomic re-sequencing data from male and female samples. Two pairs of primers (MS and MFS) were carefully designed; thus, the male-specific marker could be genotyped by PCR amplification and agarose gel electrophoresis. More importantly, this male-specific marker could also be applied to precisely identify the genetic sex of multiple fish. This male specific DNA marker will have potential applications in the elucidation of the sex determination mechanism and will also accelerate the development of sex control breeding in the large yellow croaker. Moreover, our current data further validated an significant genetic evidence that an XY-male determination mechanism is utilized in the large yellow croaker.