Even more oak species in Mexico? Genetic structure and morphological differentiation support the presence of at least two specific entities within Quercus laeta

Differentiation among populations, sometimes despite ongoing gene exchange, is a key step in speciation. Therefore, comparison of intra- and interspecific differentiation patterns is of great significance to understanding speciation. The genus Quercus is an interesting system to test speciation models in the presence of gene flow, due to its weak interspecific reproductive barriers. The aim of the present study was to characterize the degree and pattern of morphological and genetic differentiation among different morphotypes in the white oak Quercus laeta, some corresponding to the previously described species Q. centralis, Q. laeta, Q. prinopsis and Q. transmontana, as well as geographically structured variation within Q. transmontana not previously described. Our goal was to evaluate if some of these can be considered distinct specific entities or are rather part of a continuum of variation. Nine microsatellite loci and two intergenic regions of chloroplast DNA were analyzed. Morpholo...种群间的分化——即便时常伴随持续的基因交流（gene exchange）——是物种形成（speciation）过程中的关键步骤。因此，比较种内与种间的分化模式，对于理解物种形成机制具有重要意义。栎属（Quercus）因种间生殖隔离屏障较弱，是检验存在基因流条件下物种形成模型的优质实验体系。本研究的首要目标是表征白栎类群（white oak）枹栎（Quercus laeta）不同形态型之间的形态与遗传分化程度及模式，这些形态型部分对应此前已发表描述的物种：中央栎（Q. centralis）、枹栎（Q. laeta）、多脉栎（Q. prinopsis）与山地栎（Q. transmontana），此外还涵盖此前未被报道的山地栎（Q. transmontana）内部的地理结构变异。本研究的核心目标在于评估其中部分类群是否可作为独立的物种分类单元，抑或仅属于形态变异连续体的组成部分。本研究分析了9个微卫星（microsatellite）位点以及2个叶绿体DNA（chloroplast DNA）基因间区。形态学……