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Advisor(s)
Abstract(s)
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.
Description
Keywords
Chaotic genetic patchiness Cytochrome b Discrepancy Genetic connectivity Tunisian coasts Wahlund effect
Citation
Publisher
Taylor & Francis