Genetic Diversity Studies on the West African Mangrove Oyster, Crassostrea Tulipa Along the Coast of Ghana

Abstract

ABSTRACT The West African mangrove oyster, Crassostrea tulipa (Lamarck 1819) is abundant in many coastal ecosystems and they are a rich source of protein. Despite its abundance, ecological, and economic importance, little is known about their diversity and evolutionary history. There are challenges associated with the use of morphological characters only, therefore, there has been a shift to the use of genetic markers to determine the oyster species diversity and taxonomy. The study sought primarily to undertake genetic diversity studies on the West African mangrove oyster, C. tulipa occurring along the coast of Ghana by the utilization of microsatellite markers. This was an attempt to characterize and establish if the same species of C. tulipa was occurring along the coast of Ghana from the Volta estuary (Anyanui), Densu estuary, Narkwa lagoon, Amisano lagoon, Benya lagoon, Whin estuary and Dominli lagoon. The physico-chemical parameters recorded in all the seven brackish systems were within tolerable ranges. The oysters exhibited negative allometric growth in their morphometric relationships. Low genetic variability was observed within the populations (He = 0.391, FIS = 0.791) and this may be attributed to inbreeding and limited gene flow. Small to moderate genetic differentiation was discovered between the populations where the FST range was between 0.033 and 0.100. Anyanui and Narkwa populations were more genetically differentiated whiles Densu and Dominli populations were vice versa. 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.