Center of Natural History, Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
Center of Natural History, Zoological Museum, University of Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany.
Mol Phylogenet Evol. 2019 Dec;141:106608. doi: 10.1016/j.ympev.2019.106608. Epub 2019 Sep 4.
We tested the hypothesis that ecological specialization that affects dispersal promotes diversification by a comparison of the genetic structure of two sister species of door snails across their broadly overlapping ranges in the Crimean Mountains. The hypothesized effect of ecological specialization on diversification is supported by STRUCTURE analyses that showed that Mentissa gracilicosta that is restricted to limestone rocks, is subdivided into several distinct clusters, whereas all populations of the species adapted to more continuous habitat, the forests-dwelling Mentissa canalifera, were assigned to a single cluster. Furthermore, it is supported by AMOVAs that showed that a larger part of the genetic variation of M. gracilicosta is apportioned among populations than in M. canalifera. The stronger genetic differentiation of the M. gracilicosta populations corresponds to their more distinct morphological differentiation that resulted in the classification of M. gracilicosta into several geographical subspecies, whereas the more continuously distributed M. canalifera was not subdivided into subspecies. The stronger differentiation of populations of M. gracilicosta compared to M. canalifera can be ascribed to reduced gene flow between the isolated populations of M. gracilicosta and to founder events associated with the long distance dispersal events that are necessary for the colonization of isolated rocks by M. gracilicosta. In Central Europe, the Pleistocene climatic oscillations selected for species with high dispersal abilities, whereas the more stable climate in southern Europe facilitated the non-adaptive radiation of rock-dwelling door snails. Thus, the intrinsic ecological properties of these species groups contributed to the latitudinal diversity gradient.
我们通过比较门蜗牛的两个姐妹种在克里米亚山脉广泛重叠的范围内的遗传结构，检验了影响扩散的生态特化促进多样化的假设。结构分析支持生态特化对多样化的假设效应，表明仅限于石灰岩岩石的 Mentissa gracilicosta 分为几个不同的集群，而适应更连续栖息地的物种的所有种群，森林居住的 Mentissa canalifera，被分配到一个单一的集群。此外，AMOVA 分析表明，M. gracilicosta 的遗传变异更大一部分分配在种群之间，而不是在 M. canalifera 中。M. gracilicosta 种群的更强遗传分化与它们更明显的形态分化相对应，这导致了 M. gracilicosta 被分类为几个地理亚种，而分布更连续的 M. canalifera 没有被细分亚种。与 M. canalifera 相比，M. gracilicosta 种群的分化更强，可以归因于 M. gracilicosta 隔离种群之间的基因流动减少，以及与长距离扩散事件相关的奠基事件，这些事件对于 M. gracilicosta 殖民孤立岩石是必要的。在中欧，更新世气候振荡选择了具有高扩散能力的物种，而在南欧更稳定的气候则有利于非适应性辐射的岩石居住门蜗牛。因此，这些物种群体的内在生态特性促成了纬度多样性梯度。
