Abstract:A female specific random amplified polymorphic DNA (RAPD) marker was obtained in blue tilapia Oreochromis aureus through screening 800 random primers. The female specific DNA fragment with a length of 1 488 bp was cloned, sequenced, and converted into a SCAR (Sequence Characterized Amplified Region) marker, SCAROaF1488. A duplex PCR method was developed to amplify SCAROaF1488 together with a 509-bp-long mtDNA 16S rRNA gene fragment which served as a positive control. Two hundred individuals originated from 2 populations, including 100 males and 100 females, were used to verify the reliability of the SCAR marker by using the duplex PCR method. The sex identification test results of 200 fish showed 100% accordance with their phenotypic sex. SCAROaF1488 was successfully amplified in all female but not in male individuals. By contrast, the control fragment was amplified in all the males and females. The female-specific marker SCAROaF1488 developed in the present study can be used for molecular identification of genetic sex in blue tilapia. In addition, this work will provide an important tool for screening and isolation of the sex-determining locus and sex manipulation in this tilapia.
