Genetic differentiation among populations of the endangered fan mussel Pinna nobilis (Mollusca) along the Tunisian coastline

TitleGenetic differentiation among populations of the endangered fan mussel Pinna nobilis (Mollusca) along the Tunisian coastline
Publication TypeJournal Article
Year of Publication2011
AuthorsRabaoui, L, Mejri R, Tlig-Zouari S, Bahri L, Hassine OKB, Tsigenopoulos CS
JournalHydrobiologia
Volume678
Pages99-111
Keywordsfan mussel; Pinna nobilis; COI gene; “combed” and “straight and wide” shell forms; endangered; Tunisia
Abstract

The Mediterranean fan mussel Pinna nobilis is an endangered invertebrate due to overexploitation and habitat deterioration. In this species, two distinctive morphs, the “combed” and “straight and wide” forms, have been recorded and it is not known whether this morphometric variability is attributed to genetic or environmental factors. In the present study, we used mitochondrial COI sequences to describe the genetic variability of five Pinna nobilis populations sampled along the northern, eastern and southern Tunisian coastline, and to examine whether there is a genetic differentiation between the two forms of this species. DNA sequences of 675 bp from the mitochondrial COI gene have revealed ten different haplotypes among forty-nine examined specimens. Haplotype diversity was high, ranging between 0.40441 and 0.80952, and showed a decreasing North-East gradient, which seems to be explained by the hydrogeography of the study area. The mitochondrial COI marker did not suggest a genetic distinctiveness between the two Pinna nobilis shell forms, “combed” and “straight and wide”. Although the morphometric plasticity of the fan mussel could be due to the influence of environmental factors, further genetic studies using nuclear markers are envisaged to investigate whether this differentiation is associated to gene flow restrictions.

DOI10.1007/s10750-011-0827-9

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