Polyploid speciation has played an important role in evolutionary history across the tree of life, yet there remain large gaps in our understanding of how polyploid species form and persist. While systematic studies have been conducted in numerous polyploid complexes, recent advances in sequencing technology have demonstrated that conclusions from data-limited studies may be spurious and misleading. The North American gray treefrog complex, consisting of the diploid Hyla chrysoscelis and the tetraploid Hyla versicolor, has long been used as a model system in a variety of biological fields, yet all taxonomic studies to date were conducted with only a few loci from nuclear and mitochondrial genomes. Here, we utilized anchored hybrid enrichment and high-throughput sequencing to capture hundreds of loci along with whole mitochondrial genomes to investigate the evolutionary history of this complex. We used several phylogenetic and population genetic methods, including coalescent simulations and testing of polyploid speciation models with Approximate Bayesian Computation (ABC), to determine that H. versicolor was most likely formed via autopolyploidization from a now extinct lineage of H. chrysoscelis. We also uncovered evidence of significant hybridization between diploids and tetraploids where they co-occur, and show that historical hybridization between these groups led to the re-formation of distinct polyploid lineages following the initial whole genome duplication event. Our study indicates that a wide variety of methods and explicit model testing of polyploid histories can greatly facilitate efforts to uncover the evolutionary history of polyploid complexes.

中文翻译：

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北美灰树蛙基因组复制和杂交的复杂历史

多倍体物种形成在整个生命之树的进化史中发挥了重要作用，但在我们对多倍体物种如何形成和持续存在的理解方面仍然存在很大差距。尽管已经对许多多倍体复合体进行了系统的研究，但测序技术的最新进展表明，数据有限研究的结论可能是虚假的和误导性的。北美灰树蛙复合体由二倍体金黄色Hyla和四倍体Hyla versicolor组成，长期以来一直用作各种生物学领域的模型系统，但是迄今为止，所有分类学研究都只使用了几个来自核和生物的基因座。线粒体基因组。这里，我们利用锚定杂交富集和高通量测序来捕获数百个基因座以及整个线粒体基因组，以研究该复合体的进化历史。我们使用了几种系统发育和种群遗传方法，包括聚结模拟和使用近似贝叶斯计算（ABC）来测试多倍体物种形成模型，以确定杂色嗜血杆菌最有可能是通过现已灭绝的嗜血杆菌的谱系通过多倍体形成而形成的。我们还发现了二倍体和四倍体同时发生的显着杂交的证据，并表明在最初的整个基因组复制事件之后，这些群体之间的历史杂交导致了独特的多倍体谱系的重新形成。