Bandsharing Values and Genetic Distances of Two Wild Shortnecked Clam, Ruditapes philippinarum Populations from the Yellow Sea Assessed by Random Amplified Polymorphic DNAs-Polymerase Chain Reaction

Genomic DNAs were extracted from the muscle of twenty-two specimens of two shortnecked clam, Ruditapes phifippinarum populations collected in Anmyeondo and Seocheon. Genetic differences within and between populations were analysed by random amplified polymorphic DNAs-polymerase chain reaction (RAPD-PCR) using twenty arbitrary decamer primers. Out of 20 primers, 6 generated a total of 1,111 major and minor RAPD bands from individuals of two sites, producing approximately 4.2 average polymorphic bands per primer in individuals from Anmyeondo and ranging in size from less than 50 to larger than 1,500 base pairs (bp). The electrophoretic analysis of RAPD products amplified showed moderate levels of similarity among the different individuals in Seo-cheon population. The average bandsharing values (BS value) of the samples within population from Anmyeondo ranged from 0.155 to 0.684, whereas it was 0.143∼0.782 within population from Seocheon. The average BS value between individuals No. 13 and No. 14 from Seocheon was 0.782 which was higher than that of those from Anmyeondo. The single linkage dendrogram resulted from three primers (OPA-08, -09 and -20), indicating six genetic groupings composed of group 1 (No.4, 8 and 10), group 2 (No. 18), group 3 (No.2, 5 and 7), group 4 (No. 1, 3, 6, 9, 11, 12, 13, 14, 15 and 17), group 5 (16, 19 and 20) and group 6 (No. 21 and 22). In the Seocheon population, the individual No. 18 clustered distinctly from the others of this population. The observed genetic distance between the two populations from Anmyeondo and Seocheon was more than 0.209 (0.247 and 0.275). The shortest genetic distance (0.094) displaying significant molecular differences was between individuals No. 13 and No. 14. Especially, the genetic distance between individuals No. 22 and the remnants among individuals in two geographical populations was highest (0.275). This result illustrated that individual No.22 is distinct from other individuals within two shortnecked populations. The different geographical features of two sites may have caused the genetic diversity in two shortnecked clam populations.