Résumé:
The present work concerns a study of the genetic and haplotypic diversity of some populations of the two species of limpets Patella ferruginea (Gmelin, 1791) and Patella rustica (Linnaeus, 1758) carried out at the level of the Algerian, Mediterranean and Atlantic coast (P. rustica).
In order to find models of genetic structures of P. ferruginea and P. rustica populations which can highlight hot-spot zones, a phylogeographic study was carried out based on 177 sequences of the portion of the mitochondrial gene Cytochrome Oxidase I "COI" of P. ferruginea and 134 sequences of the same gene for P.rustica derived from previous studies.
In this regard, a regression between the nucleotide/haplotypic diversity and the geographical coordinates of the different populations of limpets studied at the microgeographical scale (Algerian coast) and at the macrogeographical scale (Mediterranean/Atlantic) was carried out by considering the“ longitude effect” and the “latitude effect” for the two species studied. In order to have an idea on the genetic barriers and to determine the hot-spot zones, phylogeographic analyze were carried out using several bioinformatics programs (BioEdit, DnaSp and Arlequin).
The results showed the presence of some probable hot-spot zones at the microgeographic scale such as the Bérard station (BE) and Figuier plage (FP) which could limit the diversity of P. ferruginea and P.rustica in the center of the Algerian coast according to a molecular analysis of variance (AMOVA). A hot-spot zone was also detected at the macro-geographical scale around the stations of the Alboran Sea for P.ferruginea As station of Chafarinas (CHA) and concerning P.rustica a hot-spot zone around some stations in the Canary Islands ) CIS) and Madeira (MD) has been found.
Finally, environmental differences caused by frontal ocean currents can affect the survival and reproduction of limpet larvae, which can lead to genetic divergence between populations located on either side of the frontal current. Consequently, frontal ocean currents may play an important role in forming invisible genetic barriers between limpet populations.
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