Assessment of genetic diversity and population structure in wild populations of Crassostrea tulipa in Ghana

The West African Mangrove oyster, Crassostrea tulipa (Lamarck, 1819) is abundant in many coastal aquatic ecosystems. Despite their abundance, ecological, and economic importance, little is known about its diversity and evolutionary history. There are challenges asso-ciated with the use of morphological criteria only in the characterization of organisms, therefore, there has been a shift to the use of genetic markers to determine the diver-sity and taxonomy of this oyster species. This paper seeks to characterize and establish if the species of C. tulipa occurring along the coast of Ghana was the same or if there are cryptic species occurring. Therefore, a study was conducted, using microsatellite mark-ers on seven (7) populations of oysters from the coast of Ghana. These populations are namely; Anyanui (Volta), Densu (Greater-Accra), Narkwa, Amisano and Benya (Central), Whin and Dominli (Western). Low genetic variability was observed within the populations (He = 0.391, FIS = 0.791) which was attributed to inbreeding and limited gene flow. Small to moderate genetic differentiation was observed between the populations where the FST range was between 0.033 and 0.100. Anyanui and Narkwa populations were more genet-ically differentiated whiles Densu and Dominli populations were the least differentiated. There was no relationship between genetic distance and geographical distance; therefore, the genetic structure of C. tulipa occurring along the coast of Ghana did not follow any geographical pattern of distribution. It appeared clearly that the populations of C. tulipa occurring along the coast of Ghana from the studied sites may be of multiple populations. This calls for the attention of interested parties to help in the sustainability of these oys-ter populations which are vulnerable to natural selection pressures that can lead to the driving down of their existence.(c) 2022 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )