Sex Determination Systems Based on PCR for Salmonids Reared in Ukraine

Abstract

Aims. To analyse highly conserved male-specifi c sequences in Y chromosome of salmonid species and de- velop the conventional polymerase chain reaction (PCR) for rapid identifi cation of fi sh sex. Methods. DNA sequence analysis, phylogenetic analysis, DNA extraction, primers design, PCR and sequencing were used. Results. Using the data from NCBI GenBank, all available sequences of male-specifi c Y-chromosome genes (sdY) in salmonid species were analyzed for specifi c oligonucleotide primer design. The PCR assay for rapid identifi cation of males in rainbow trout Onchorhynchus mykiss, brown trout Salmo trutta, huchen Hucho hucho and grayling Thymallus thymallus was developed. The length of PCR products was in the range of 200–800 base pairs (bp). The specifi city of the amplifi ed fragments was tested by sequencing of PCR products. All PCR products corresponded to the areas of the Y chromosome where the sdY loci are located. The comparison of the amplifi ed DNAs revealed high identity (95–99 %) between the sequences of the rainbow trout, the brown trout, the huchen, and the grayling. The highest identity rates were noted among one specifi c genus and the percent- age of homology was approximately 99 % as shown for rainbow trout O. mykiss. Conclusions. The sex of the mentioned above fi sh species can be readily determined by the PCR assay which allows performing simple identifi cation of “neomales” in the indirect feminization method via the hormonal sex reversal. The assay can be classifi ed as express diagnostics, because the data analysis and the delivery of the generated results to the fi sh-farming site can be accomplished within a day.