Data from: Speciation by genome duplication: repeated origins and genomic composition of the recently formed allopolyploid species Mimulus peregrinus

Whole genome duplication (polyploidisation) is a mechanism of “instantaneous” species formation that has played a major role in the evolutionary history of plants. Much of what we know about the early evolution of polyploids is based upon studies of a handful of recently formed species. A new polyploid hybrid (allopolyploid) species Mimulus peregrinus, formed within the last 140 years, was recently discovered on the Scottish mainland and corroborated by chromosome counts. Here, using targeted, high-depth sequencing of 1200 genic regions, we confirm the parental origins of this new species from M. x robertsii, a sterile triploid hybrid between the two introduced species M. guttatus and M. luteus that are naturalised and widespread in the United Kingdom. We also report a new population of M. peregrinus on the Orkney Islands and demonstrate that populations on the Scottish mainland and Orkney Islands arose independently via genome duplication from local populations of M. x robertsii. Our data raise the possibility that some alleles are already being lost in the evolving M. peregrinus genomes. The recent origins of a new species of the ecological model genus Mimulus via allopolyploidisation provide a powerful opportunity to explore the early stages of hybridisation and genome duplication in naturally evolved lineages.

全基因组复制（polyploidisation）是一种“瞬时”物种形成机制，在植物演化历史中发挥了关键作用。当前学界对多倍体早期演化的认知，大多基于对少数新近形成物种的研究。一种形成于过去140年内的异源多倍体（allopolyploid）杂交新种——沟酸浆属（Mimulus）Mimulus peregrinus，近期在苏格兰本土被发现，并经染色体计数得到验证。本研究通过对1200个基因区域开展靶向高深度测序，证实该新种的亲本起源为罗伯茨沟酸浆（M. x robertsii）：该不育三倍体杂交种由两种已在英国归化且广泛分布的引入种斑点沟酸浆（M. guttatus）与黄色沟酸浆（M. luteus）杂交而来。本研究还报道了在奥克尼群岛发现的M. peregrinus新种群，并证实苏格兰本土与奥克尼群岛的该物种种群，均独立由当地罗伯茨沟酸浆种群经基因组复制形成。本研究数据提示，在演化中的M. peregrinus基因组内，部分等位基因或已发生丢失。作为生态模式属沟酸浆属通过异源多倍化形成的新近物种，该新种为探究自然演化谱系中杂交与基因组复制的早期阶段提供了极佳的研究契机。