背景:古老湖泊中的物种蜂拥而至,特别是那些来自自适应辐射的辐射,构成了这些岛屿生态系统中整体分类和形态多样性的大部分。对于这些主要是年轻物种的组合,到目前为止,经典的线粒体条形码标记是解开种间关系的关键。然而,随着下一代测序(NGS)方法和绘图工具的兴起和进一步发展,即使对于非模型组,全基因组数据也已成为越来越重要的信息来源。
结果:这里,我们提供,第一次,苏拉威西岛特有的淡水腹足类动物的综合有丝分裂基因组数据集,因此一般是古老的湖泊无脊椎动物群。我们对总共78个个体进行了低覆盖率全基因组测序,其中包括来自马利湖系统的28个Tylomelania形态物种中的27个,以及来自Poso湖和邻近流域的选定代表。我们的目的是评估有丝分裂基因组是否对这个年轻物种群中的系统发育分辨率做出了重大贡献。有趣的是,我们在其他“非传统”线粒体基因座中发现了大量的可变和简约信息位点。然而,尽管总体支持度很高,获得的拓扑结构与先前发表的单基因座系统发育基本一致。几个进化枝仍未解决,许多物种被恢复,表明快速多样化和线粒体基因渗入。
结论:这再次说明,尽管可用的字符数量较多,有丝分裂基因组表现得像一个单一的基因座,因此只能对解决物种边界做出有限的贡献,特别是当涉及渗入事件时。
BACKGROUND: Species flocks in ancient lakes, and particularly those arising from adaptive radiation, make up the bulk of overall taxonomic and morphological diversity in these insular ecosystems. For these mostly young species assemblages, classical mitochondrial barcoding markers have so far been key to disentangle interspecific relationships. However, with the rise and further development of next-generation sequencing (NGS) methods and mapping tools, genome-wide data have become an increasingly important source of information even for non-model groups.
RESULTS: Here, we provide, for the first time, a comprehensive mitogenome dataset of freshwater gastropods endemic to Sulawesi and thus of an ancient lake invertebrate species flock in general. We applied low-coverage whole-genome sequencing for a total of 78 individuals including 27 out of the 28 Tylomelania morphospecies from the Malili lake system as well as selected representatives from Lake Poso and adjacent catchments. Our aim was to assess whether mitogenomes considerably contribute to the phylogenetic resolution within this young species flock. Interestingly, we identified a high number of variable and parsimony-informative sites across the other \'non-traditional\' mitochondrial loci. However, although the overall support was very high, the topology obtained was largely congruent with previously published single-locus phylogenies. Several clades remained unresolved and a large number of species was recovered polyphyletic, indicative of both rapid diversification and mitochondrial introgression.
CONCLUSIONS: This once again illustrates that, despite the higher number of characters available, mitogenomes behave like a single locus and thus can only make a limited contribution to resolving species boundaries, particularly when introgression events are involved.