Population Genetic Analysis of Rainbow Clam Moerella iridescens by Using rDNA

Abstract

To assess the genetic background of the germplasm resource of rainbow clam Moerella iridescens along China coasts, population genetic structure and genetic diversity of rainbow clam from five geographical populations in the Yellow Sea and the East China Sea (Lianyungang, Chongming, Cixi, Zhoushan, and Ningde) were analyzed based on rDNA (ITS1-5.8S-ITS2) sequences. Forty-Seven rDNA haplotypes were identified among 109 rainbow clam individuals of the five populations. Gen4 and Gen21 were the dominant haplotypes, accounting for 49.5% of rDNA whole gene sequences, and shared by the five populations. Six to eight exclusive haplotypes were found in each population. The average haplotype diversity index (HD) of the five populations was 0.8733. The genetic distance among populations ranged from 0.002 to 0.004, and haplotypes from the same population were not clustered in a single clade. Molecular variance analysis (AMOVA) demonstrated that the main genetic differentiation mainly occurred within population, and the genetic differentiation coefficient (FST) among five populations was between -0.02836 and 0.01896, which meant that no genetic differentiation among populations occurred. Overall, the five geographical populations showed a high genetic diversity, but no evident genetic structure or genetic differentiation.