Phylogeographic inferences from the mtDNA variation of the three-toed skink, Chalcides chalcides (Reptilia: Scincidae).
Genetic diversity was analyzed in Chalcides chalcides populations from peninsular Italy, Sardinia, Sicily and Tunisia by sequencing 400 bp at the 5' end of the mitochondrial gene encoding cytochrome b (cyt b) and by restriction fragment length polymorphism (RFLP) analysis of two mitochondrial DNA segments (ND-1/2 and ND-3/4). The results of the phylogenetic analysis highlighted the presence of three main clades corresponding with three of the four main geographical areas (Tunisia, Sicily and the Italian peninsula), while Sardinia proved to be closely related to Tunisian haplotypes suggesting a colonization of this island from North Africa by human agency in historical times. On the contrary, the splitting times estimated on the basis of cyt b sequence data seem to indicate a more ancient colonization of Sicily and the Italian Peninsula, as a consequence of tectonic and climatic events that affected the Mediterranean Basin during the Pleistocene. Finally, the analysis of the genetic variability of C. chalcides populations showed a remarkable genetic homogeneity in Italian populations when compared to the Tunisian ones. This condition could be explained by a rapid post-glacial expansion from refugial populations that implied serial bottlenecking with progressive loss of haplotypes, resulting in a low genetic diversity in the populations inhabiting the more recently colonized areas.
Giovannotti
Massimo
M
Istituto di Biologia e Genetica, Università Politecnica delle Marche, I-60100 Ancona, Italy.
Cerioni
Paola Nisi
PN
Kalboussi
Mohsen
M
Aprea
Gennaro
G
Caputo
Vincenzo
V
D000704:Analysis of Variance; D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D003198:Computer Simulation; D004272:DNA, Mitochondrial / Q000235:genetics*; D003710:Demography; D014644:Genetic Variation; D005828:Genetics, Population; D005843:Geography; D007558:Italy; D008116:Lizards / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA; D014416:Tunisia
D004272:DNA, Mitochondrial