Data from: Rapid genetic assimilation of native wall lizard populations (Podarcis muralis) through extensive hybridization with introduced lineages

The Common Wall Lizard (Podarcis muralis) has established more than 150
non-native populations in Central Europe, stemming from eight
geographically distinct evolutionary lineages. While the majority of these
introduced populations are found outside the native range, some of these
populations also exist at the northern range margin in south-western
Germany. In order to a) infer the level of hybridization in contact zones
of alien and native lineages and b) compare the genetic diversity among
purebred introduced, native and hybrid populations we used a combination
of maternally inherited markers (mtDNA: cytb) and Mendelian markers
(microsatellites). Our results suggest a rapid genetic assimilation of
native populations by strong introgression from introduced lineages.
Discordant patterns of mtDNA and nDNA variation within hybrid populations
may be explained by directed mate choice of females towards males of alien
lineages. In contrast to previous studies we found a non-linear
relationship between genetic diversity and admixture level. The genetic
diversity of hybrid populations was substantially higher than in
introduced and native populations belonging to a single lineage, but
rapidly reaching a plateau of high genetic diversity at an admixture level
of two. However, even introduced populations with low founder sizes and
from one source population retained moderate levels of genetic diversity
and no evidence for a genetic bottleneck was found. The extent of
introgression and the dominance of alien haplotypes in mixed populations
indicate that introductions of non-native lineages represent a serious
threat to the genetic integrity of native populations due to the rapid
creation of hybrid swarms.