Open AccessGenetic variation and its evolutionary implications in a Mediterranean island endemic lizard
Author(s) -
SALVI DANIELE,
CAPULA MASSIMO,
BOMBI PIERLUIGI,
BOLOGNA MARCO A.
Publication year - 2009
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2009.01313.x
Subject(s) - biology , sympatric speciation , genetic variation , gene flow , genetic structure , population fragmentation , genetic drift , evolutionary biology , biological dispersal , genetic variability , local adaptation , ecology , mediterranean islands , population genetics , population , mediterranean climate , genetics , genotype , demography , sociology , gene
The peculiar bioclimatic and geographic features of Corso–Sardinian islands may provide an ideal scenario for investigating microevolutionary processes, given their large heterogeneity of environments, which could affect dispersal and gene flow among populations, as well as processes of local adaptation. The genetic variation and differentiation among populations of the endemic lizard Archaeolacerta bedriagae were studied by allozyme electrophoresis at 20 presumptive loci. The genetic structure of this species is characterized by relatively high levels of polymorphism and low differentiation among populations. The pattern of genetic differentiation cannot be explained by genetic drift as a function of geographic distance. Genetic distance data show that genetic variation is distributed into three geographically coherent population groups and suggest a recent (Late Pleistocene) origin for the observed geographic fragmentation. The analysis of environmental correlates of allozymic variation indicates a strong correlation of the Idh‐1 locus with climatic variables. The frequency of the Idh‐1 106 allele is negatively correlated with annual temperature, and positively correlated with annual precipitation. In addition, the observed heterozygosity at this locus decreases towards more arid climatic regimes. The results obtained support the assumption of differential selection acting on Idh‐1 allozymes under diverse climates. An association between Idh‐1 allozymes and local bioclimatic regimes was also observed for the sympatric lizard Podarcis tiliguerta , suggesting a key role for such selective agents on Idh‐1 polymorphism in these two Corso–Sardinian lacertids. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 661–676.