Van Linden Lisa, Svardal Hannes, Štambuk Anamaria, Herrel Anthony, Van Damme Raoul
Functional Morphology Laboratory, Department of Biology, University of Antwerp, Antwerp, Belgium.
Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia.
Oecologia. 2025 Jul 8;207(7):125. doi: 10.1007/s00442-025-05769-2.
The successful establishment of small founding populations introduced into novel environments often represents a paradox, given the genetic challenges they face. Genetic admixture, whether intra- or interspecific, may offer a solution by enhancing the genetic diversity and adaptability of the population. Here, we explore the role of genetic admixture in the rapid establishment and adaptation of the Italian wall lizard (Podarcis siculus) introduced on Pod Mrčaru, a small islet in the Adriatic Sea. Introduced in 1971 in a small group of ten individuals from a nearby island, this population rapidly adapted to its new environment, outcompeting the native Dalmatian wall lizard (Podarcis melisellensis) and exhibiting striking ecological and phenotypic shifts. Using whole-genome sequencing data from P. siculus populations on Pod Mrčaru and neighbouring islands and from P. melisellensis, we investigated population structure, admixture, and gene flow to test whether inter- or intraspecific genetic exchange contributed to the successful establishment and divergence of the introduced population. Despite the sympatric presence of P. melisellensis during the introduction of P. siculus on Pod Mrčaru, and thus the opportunity for genetic exchange, we found no evidence of hybridisation between the two species. Even amongst neighboring island populations of P. siculus, we observed only limited gene flow, suggesting relatively independent evolution of the populations since their establishment on the islands. These findings highlight the potentially significant roles of distinct selective pressures and/or ecological and phenotypic plasticity, rather than genetic exchange, in driving the population's rapid adaptation to a novel environment.
考虑到新引入的小种群在新环境中面临的遗传挑战，其成功建立往往是一个悖论。遗传混合，无论是种内还是种间的，都可能通过增强种群的遗传多样性和适应性来提供一种解决方案。在这里，我们探讨了遗传混合在引入亚得里亚海一个小岛上的意大利壁蜥（Podarcis siculus）快速建立和适应过程中的作用。1971年，一小群来自附近岛屿的十只意大利壁蜥被引入该岛，这个种群迅速适应了新环境，胜过了当地的达尔马提亚壁蜥（Podarcis melisellensis），并表现出显著的生态和表型变化。利用来自姆尔查鲁岛及邻近岛屿上的意大利壁蜥种群以及达尔马提亚壁蜥的全基因组测序数据，我们研究了种群结构、混合情况和基因流，以测试种间或种内的遗传交换是否促成了引入种群的成功建立和分化。尽管在将意大利壁蜥引入姆尔查鲁岛时达尔马提亚壁蜥与其同域共存，因而存在遗传交换的机会，但我们没有发现这两个物种之间杂交的证据。即使在意大利壁蜥的邻近岛屿种群之间，我们也仅观察到有限的基因流，这表明这些种群自建立在这些岛屿上以来相对独立地进化。这些发现突出了独特的选择压力和/或生态及表型可塑性而非遗传交换在推动种群快速适应新环境方面可能发挥的重要作用。
