Genetic Diversity and Variation in Mitochondrial COI Gene in Wild and Hatchery Populations of Saxidomus purpuratus

Abstract

To investigate the genetic diversity and genetic variations of four wild (Geoje, Jinhae, Yeosu, and Boryeong) and two hatchery (Goheung and Geoje) populations of purplish Washington clam (Saxidomus purpuratus), 421 bp sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene were analyzed. A total of 149 haplotypes were identified from 358 individuals from the four wild and two hatchery populations with 109 substitutions. The genetic diversity of the wild populations and Geoje hatchery population were high, whereas the total number of haplotypes, population-specific haplotypes, and haplotype diversity were comparatively low in the Goheung hatchery population. The fixation index (F-ST) indicated that there was no significant genetic difference between the four wild populations. However, the Goheung hatchery population was significantly different from that of the Geoje hatchery, exhibiting the most pronounced difference, and two wild populations (Jinhae and Yeosu). The low genetic diversity indices exhibited by the Goheung hatchery population might have resulted from farm propagation using a limited parental stock. Therefore, to maintain genetic diversity, a proper breeding management program using more progenitors is required in hatcheries, in addition to regular monitoring of both hatchery and wild populations.