Data from: Genetic diversity and historical biogeography of the Maltese wall lizard, Podarcis filfolensis (Squamata: Lacertidae)

Podarcis filfolensis is an endemic lizard from the Maltese archipelago. There is evidence of human-mediated decline and even extirpation of some insular populations of this species. However, information about the intraspecific genetic diversity and phylogeographic patterns of this species is limited. Here we analyze genetic markers from a multi-locus dataset (mtDNA, 2,533 bp; nuclear c-mos gene, 353 bp; 11 microsatellites) for individuals from extant populations of P. filfolensis. Despite generally low genetic variability, two main mitochondrial groupings were clearly identified. In general, individuals from the main island of Malta were genetically distinct from those from Gozo, Comino, Cominotto and Small Blue Lagoon Rock, and also from Linosa and Lampione individuals. Three genetic clusters were detected based on microsatellite data: one was found at higher frequency on Malta, while the other two included samples from the remaining islands, showing some concordance with the mtDNA pattern. A time-calibrated Bayesian tree for the principal mitochondrial lineages indicated strong statistical support for two P. filfolensis lineages that originated in the Pleistocene (105.4–869 Ka). We show that these lineages largely meet the criteria for recognition as evolutionary significant units despite some recent admixture (possibly due to recent translocations between islands). Human disturbance, low genetic variability, evidence of bottlenecks and extirpation on one island indicate that a thorough review of the current conservation status of P. filfolensis would be timely.

菲氏壁蜥（Podarcis filfolensis）是马耳他群岛特有的蜥蜴物种。已有研究证实，该物种种群中部分岛屿种群存在人类活动介导的衰退甚至局部灭绝现象。然而，目前关于该种种内遗传多样性与系统地理格局的研究信息仍较为匮乏。本研究针对现存的菲氏壁蜥种群个体，基于多座位数据集（multi-locus dataset）开展遗传标记分析，该数据集包含线粒体DNA（mtDNA，2533 bp）、核c-mos基因（nuclear c-mos gene，353 bp）以及11个微卫星标记（microsatellites）。尽管整体遗传变异水平较低，但研究仍清晰鉴定出两个主要的线粒体支系集群。总体而言，马耳他主岛的个体与戈佐岛、科米诺岛、科米诺托岛、小蓝礁湖岩以及利诺萨岛、兰皮奥内岛的个体在遗传层面存在显著分化。基于微卫星数据，研究共检测到三个遗传簇：其中一个在马耳他岛的个体中占比更高，另外两个则涵盖其余岛屿的样本，该结果与线粒体DNA的聚类模式存在一定一致性。针对主要线粒体支系构建的时间校准贝叶斯树（time-calibrated Bayesian tree）显示，两个起源于更新世（Pleistocene，105.4–869 Ka）的菲氏壁蜥支系得到了强有力的统计学支持。尽管近期存在一定程度的基因交流（可能源于岛屿间近年的人为迁移），但本研究证实这两个支系在很大程度上符合进化显著单元（evolutionary significant units）的认定标准。人类活动干扰、较低的遗传变异水平、种群瓶颈的相关证据以及某一岛屿上的局部灭绝现象，均表明亟需对菲氏壁蜥的当前保护现状开展全面评估与梳理。