Mention Zoologie et Biodiversité Animale, Université d'Antananarivo, Antananarivo, Madagascar.
Association Vahatra, Lot V A 38 LBA Ter Ambohidempona Tsiadana, Antananarivo, Madagascar.
PLoS One. 2022 Mar 31;17(3):e0263764. doi: 10.1371/journal.pone.0263764. eCollection 2022.
In the processes that give rise to new species, changes first occur at the population level. But with the continuous nature of the divergence process, change in biological properties delimiting the shift from "individuals of divergent populations" towards "individuals of distinct species", as well as abiotic factors driving the change, remain largely ambivalent. Here we study diversification processes at the population level in a semi-aquatic frog, Mantidactylus (Brygoomantis) bellyi, across the diverse vegetation types of Montagne d'Ambre National Park (MANP), Madagascar. Genetic diversity was assessed with seven newly developed microsatellite markers as well as mitochondrial DNA sequences and concordance with patterns of ecological, morphological, and bioacoustic divergence evaluated. We found M. bellyi lacking mitochondrial differentiation within MANP, while microsatellite datasets partitioned them into three highly differentiated, geographically separated subpopulations (with indications for up to five subpopulations). The molecular grouping-primarily clustering individuals by geographic proximity-was coincident with differences in mean depth and width of waters, suggesting a possible role of fluvial characteristics in genetic exchange in this stream-breeding species. Genetic clustering not consistent with differences in call properties, except for dominant call frequencies under the two-subpopulations model. Morphological divergence was mostly consistent with the genetic clustering; subpopulations strongly differed by their snout-vent length, with individuals from high-elevation subpopulations smaller than those from populations below 1000 m above sea level. These results exemplify how mountains and environmental conditions might primarily shape genetic and morphological divergence in frog populations, without strongly affecting their calls.
在产生新物种的过程中，变化首先发生在种群水平。但是，随着分化过程的持续，生物特性的变化界定了从“分化种群的个体”向“不同物种的个体”的转变，以及驱动变化的非生物因素，仍然在很大程度上存在矛盾。在这里，我们研究了马达加斯加安布埃山国家公园（MANP）多样化植被类型中半水生青蛙 Mantidactylus（Brygoomantis）bellyi 的种群水平多样化过程。使用新开发的七个微卫星标记以及线粒体 DNA 序列评估了遗传多样性，并与生态、形态和生物声学分化的模式进行了一致性评估。我们发现 M. bellyi 在 MANP 内没有线粒体分化，而微卫星数据集将它们分为三个高度分化的、地理上分离的亚种群（有多达五个亚种群的迹象）。分子分组——主要是根据地理接近度对个体进行聚类——与水深和宽度的差异一致，表明河流特征在这种溪流繁殖物种的基因交换中可能起作用。遗传聚类与叫声特性的差异不一致，除了在两亚种群模型下的主要叫声频率。形态分化与遗传聚类基本一致；亚种群在吻肛长上有强烈差异，高海拔亚种群的个体比海拔 1000 米以下的种群小。这些结果说明了山脉和环境条件如何主要塑造了青蛙种群的遗传和形态分化，而对它们的叫声影响不大。
