Hybrid Origin of the Thai-Chitralada Tilapia Strain Using DNA Barcoding and Microsatellite Analysis

Abstract

The Thai-Chitralada strain originates from Egypt and was transferred to Japan. From there a stock of 50 fish were introduced to the Royal Chitralada Palace in Thailand. The commercially cultured strain of Nile tilapia O. niloticus in Thailand, Thai-Chitralada, possesses desirable traits for aquaculture, such as high growth rate integrated with reasonable fecundity and excellent performance in Asian countries. In 2010 a few dozen Thai-Chitralada fish were introduced to Israel from Thailand. The objective of this study is to trace the origin of Thai-Chitralada using DNA barcoding and microsatellite genetic markers. Cytochrome Oxidase I and D-loop sequences of 19 Thai-Chitralada fish clustered into three groups comprising 6, 7, and 6 individuals were homologous to the consensus sequences of O. aureus, O. niloticus, and O. mossambicus, respectively. The allele ranges for microsatellites UNH168 and G7A exclude O. niloticus (Ghana) as potential contributor to the ThaiChitralada strain. Genotyping for three microsatellites indicate overlap of alleles between Thai-Chitralada and O. niloticus (Egypt) and O. aureus, while O. mossambicus was not tested. Thus, our data based on mitochondrial and genomic analyses demonstrate that O. aureus, O. niloticus (Egypt), and O. mossambicus contributed to the formation of Thai-Chitralada. Thai-Chitralada can be used as a genetic resource for selection and adaptation to different geographical regions because of its diverse genetic background and desirable traits.