GENETIC-VARIATION WITHIN AND BETWEEN 2 TYRRHENIAN POPULATIONS OF THE MEDITERRANEAN ALCYONARIAN CORALLIUM-RUBRUM

Allozymic variation of 13 gene loci was investigated in 2 samples of Corallium rubrum (L.) collected in the Tyrrhenian Sea (Tuscany, Italy), at the coastal Calafuria cliff (south of Leghorn) and at Elba Island (Tuscan Archipelago) respectively. Among 5 polymorphic loci, Pgm and Pgi showed the highest level of heterozygosity. In the Elba sample all polymorphic loci were in Hardy-Weinberg equilibrium, whereas in the Calafuria sample, Pgm and Pgi were not. Mixing of individuals from genetically different subpopulations (Wahlund effect) may cause this disequilibrium. Nei's indices together with F-statistics show that the samples investigated can be considered as 2 distinct local populations. The results suggest that limited larval dispersal may be more important in promoting C. rubrum population differentiation than differential selection on the migrating larvae.