Genetic variability in mainland and insular populations of Podarcis muralis (Reptilia: Lacertidae)

摘要

Allozyme electrophoresis was used to study the distribution of genetic variation within and among mainland and insular populations of the lacertid lizard Podarcis muralis from western, southern and eastern Europe. Genetic variability in the species islow and genetic subdivision is high. The highest values of percent polymorphism and heterozygosity were found in the samples from two Tyrrhenian islands (Elba Island, La Scola Islet). The occurrence of higher levels of genetic variability in insular populations is probably because these populations inhabit marginal environments characterized by temporal-ecological instability. In these environments high heterozygosity levels can be preserved after colonization events, unless founder populations are sosmall that bottleneck effects occur. The genetic heterogeneity analysis demonstrates a certain amount of genetic differentiation among local populations of P. muralis, with a relatively high level of genetic subdivision. Allozyme data show that genetic variation in P. muralis is distributed into two major population groups: the first includes the closely related samples from Spain and SW France, the second the genetically recognizable samples from Germany, Italy, and Greece. The average genetic distancebetween the two groups is relatively high (Nei's D = 0.059), with D ranging from 0.043 to 0.100.