Variabilite genetique entre les classes d'age chez le pageot commun Pagellus erythrinus Sparidae des cotes nord tunisiennes.

Abstract

Genetic variability between age groups of the common pandora, Pagellus erythrinus , (Linnaeus, on 1758; Sparidae) was examined by allozyme markers. The study was carried out using 251 specimens, collected from the North Tunisians coasts. Ages were estimated indirectly from fish otoliths. The fourteen enzymatic systems used are encoded by 21 loci, among which 10 are polymorphic at a level of 99%. The mean unbiased expected heterozygosity (H sub(nb) = 0.048) is comparable to those who was reported in ichthyologic species, including Sparid family. The verification of the Hardy-Weinberg equilibrium showed a significant deviation from panmixia with heterozygotes deficiency (F sub(IS) = 0.116, p < 0.001). The genetic diversity index (F sub(ST)) obtained was 0.0004. This value indicates no significant genetic differentiation between age groups suggesting temporal stability. Finally, comparison of genetic diversity revealed an increasing of H sub(nb) values concurrent with age, supporting the sweepstakes-chance matching hypothesis.