PROMOTING ACCESS TO AFRICAN RESEARCH

African Journal of Marine Science

Log in or Register to get access to full text downloads.

Remember me or Register



DOWNLOAD FULL TEXT Open Access  DOWNLOAD FULL TEXT Subscription or Fee Access

Allozyme and mtDNA variation of white seabream Diplodus sargus populations in a transition area between western and eastern Mediterranean basins (Siculo-Tunisian Strait)

M Kaouèche, L Bahri-Sfar, M González-Wangüemert, Á Pérez-Ruzafa, OK Ben Hassine

Abstract


To investigate the possible influence of the Siculo-Tunisian Strait on the genetic structure of white seabream Diplodus sargus, 13 polymorphic allozyme loci and a fragment of the cytochrome b mitochondrial DNA were analysed. Allozyme data indicated a moderate but significant differentiation between some north-eastern (Bizerta, Ghar El Melh Lagoon and Mahdia) and southern (Gabes Gulf and El Biban Lagoon) samples. This heterogeneity was also highlighted after removing PGM* and PGI-1* loci which may be under selection. These results can be explained by the chaotic genetic patchiness hypothesis. In contrast, the mtDNA data indicated genetic homogeneity among localities showing the absence of structure in white seabream populations across the Siculo-Tunisian Strait. Historical demography of this species suggests that it has undergone a recent population expansion as a consequence of a bottleneck event during the Pleistocene glaciations.

Keywords: chaotic genetic patchiness, cytochrome b, discrepancy, genetic connectivity, Tunisian coasts, Wahlund effect

African Journal of Marine Science 2011, 33(1): 79–90



http://dx.doi.org/10.2989/1814232X.2011.572342
AJOL African Journals Online