Low Genetic Diversity and Moderate Genetic Differentiation Among Wild Populations of Crassostrea Tulipa Revealed by Simple Sequence Repeat Analysis: Implications for Conservation and Breeding

English

A good understanding of key genetic diversity traits is necessary to meet current conservationneeds and also to allow for diversification through aquaculture production. Thus, in this study, weanalyzed the genetic variation and population structure at twelve microsatellite DNA loci and atfour geographic locations of C. tulipa in Southern Ghana. From the results, the observedheterozygosity(Ho) ranged from 0.083 to 0.25. Both Volta and Densu populations recorded samevalues for expected heterozygosity (He), 0.125 and Shannon’s information index (I), 0.173, whilesNakwa and Whin were also the same, with He of 0.042 and I of 0.058 representing relatively lowdiversity. A mean private allele frequency(0.167) was recorded for 3 populations. AMOVArevealed moderate genetic differentiation among populations (6.0% of total variance, P = 0.001),consistent with the gene differentiation coefficient (FST = 0.069) and gene flow (Nm = 3.39). Thefour C. tulipa populations clustered into two distinct groups, with a weak correlation between thegeographic and genetic distances. (Mantel’s test, r = 0.014; p= 0.200). The low population geneticdiversity and moderate differentiation among C. tulipa populations, reveals the necessity topreserve the two detected clusters, as two conservation and management units. In addition to insitu conservation, ex-situ germplasm collections, focusing on as many populations as possible forbreeding and resources protection are required. Particularly, taking into account the populationswith relatively high levels of genetic diversity along with those rich in private alleles as they couldcontribute peculiar traits to increase the heterozygosity of base stocks for aquaculture.

Rhoda Lims Diyie, Samuel Addo, Emmanuel Armah, Charles Boateng, Judith Wayo, Mike Y. Osei-Atweneboana