Data from: Congruent signals of population history but radically different patterns of genetic diversity between mitochondrial and nuclear markers in a mountain lizard

Historical factors, current population size, population connectivity and selective processes at linked loci contribute to shaping contemporary patterns of neutral genetic diversity. It is now widely acknowledged that nuclear and mitochondrial markers react differently to current demography as well as to past history, so the use of both types of markers is often advocated to gain insight on both historical and contemporary processes. We used 12 microsatellite loci genotyped in 13 populations of a mountain lizard (Iberolacerta bonnali) to test if the historical scenario favoured by a previous mitochondrial study was also supported by nuclear markers and thereby evaluated the consequences of post-glacial range movements on nuclear diversity. Congruent signals of recent history were revealed by nuclear and mitochondrial markers using an Approximate Bayesian Computation approach but contemporary patterns of mtDNA and nuclear DNA diversity were radically different. This strongly impoverished mtDNA diversity, without change in nuclear DNA diversity, has been interpreted as evidence of a selective sweep of mtDNA variants in other species. However we suggest that, on the contrary, it can be explained by the different effective population size of these markers, and perhaps also by sex-biased dispersal during postglacial range expansion. Although dispersal in this species is probably highly restricted at all spatial scales, colonisation abilities have been historically good, suggesting capability for reestablishment of locally extinct populations except in fully disconnected habitats.