Ongoing hybridization obscures phylogenetic relationships in the Drosophila subquinaria species complex
Ongoing hybridization obscures phylogenetic relationships in the Drosophila subquinaria species complex
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DOI：
10.1111/jeb.13512
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发表时间：
2019-08-22
影响因子：
2.1
通讯作者：
Dyer, Kelly A.
中科院分区：
文献类型：
--
作者：
Ginsberg, Paul S.;Humphreys, Devon P.;Dyer, Kelly A.
推断最近分化的谱系之间的进化关系对于理解隔离障碍如何产生独立的谱系是必要的。在这里，我们研究了三种不完全分离且密切相关的食蘑菇果蝇物种之间的系统发育关系。这些物种形成了果蝇 subquinaria 物种复合体，由一种欧亚物种 (D. transversa) 和两种广泛分布的北美物种 (D. subquinaria 和 D. recens) 组成，它们在加拿大中部同域分布。尽管这些物种之间的交配前和交配后隔离模式已得到很好的表征，但之前对其系统发育关系的研究有限且相互矛盾。在这项研究中，我们生成了一个由 29 个基因座组成的多基因座数据集，这些数据集来自对每个物种的种群样本进行测序的基因组，然后，我们推断了物种关系和基因渗入模式。我们发现强有力的统计支持D. subquinaria是并系群，表明来自与D. recens同域的地理区域的样本与D. recens最密切相关，而来自与D. recens异域的地理区域的样本与D. transversa最密切相关。我们提出了几条证据，表明不完整的谱系排序和基因流都导致了系统发育的不一致。我们认为，持续的基因流主要从 D. recens 进入 D. subquinaria 分布范围的同域部分，导致这些物种的进化历史中系统发育的不确定性。我们的结果强调了如何利用群体遗传数据来理清密切相关物种之间系统发育不一致的根源。
Inferring evolutionary relationships among recently diverged lineages is necessary to understand how isolating barriers produce independent lineages. Here, we investigate the phylogenetic relationships between three incompletely isolated and closely related mushroom-feeding Drosophila species. These species form the Drosophila subquinaria species complex and consist of one Eurasian species (D. transversa) and two widespread North American species (D. subquinaria and D. recens) that are sympatric in central Canada. Although patterns of pre- and post-mating isolation among these species are well characterized, previous work on their phylogenetic relationships is limited and conflicting. In this study, we generated a multi-locus data set of 29 loci from across the genome sequenced in a population sample from each species, and then, we inferred species relationships and patterns of introgression. We find strong statistical support that D. subquinaria is paraphyletic, showing that samples from the geographic region sympatric with D. recens are most closely related to D. recens, whereas samples from the geographic region allopatric with D. recens are most closely related to D. transversa. We present several lines of evidence that both incomplete lineage sorting and gene flow are causing phylogenetic discordance. We suggest that ongoing gene flow primarily from D. recens into D. subquinaria in the sympatric part of their ranges causes phylogenetic uncertainty in the evolutionary history of these species. Our results highlight how population genetic data can be used to disentangle the sources of phylogenetic discordance among closely related species.