Data from: Origin and genome evolution of polyploid green toads in Central Asia: evidence from microsatellite markers

Polyploidization, which is expected to trigger major genomic reorganizations, occurs much less commonly in animals than in plants, possibly because of constraints imposed by sex-determination systems. We investigated the origins and consequences of allopolyploidization in Palearctic green toads (Bufo viridis subgroup) from Central Asia, with three ploidy levels and different modes of genome transmission (sexual versus clonal), to (i) establish a topology for the reticulate phylogeny in a species-rich radiation involving several closely related lineages and (ii) explore processes of genomic reorganization that may follow polyploidization. Sibship analyses based on 30 cross-amplifying microsatellite markers substantiated the maternal origins and revealed the paternal origins and relationships of subgenomes in allopolyploids. Analyses of the synteny of linkage groups identified three markers affected by translocation events, which occurred only within the paternally inherited subgenomes of allopolyploid toads and exclusively affected the linkage group that determines sex in several diploid species of the green toad radiation. Recombination rates did not differ between diploid and polyploid toad species, and were overall much reduced in males, independent of linkage group and ploidy levels. Clonally transmitted subgenomes in allotriploid toads provided support for strong genetic drift, presumably resulting from recombination arrest. The Palearctic green toad radiation seems to offer unique opportunities to investigate the consequences of polyploidization and clonal transmission on the dynamics of genomes in vertebrates.

多倍化（polyploidization）被认为会引发大规模基因组重排，其在动物中的发生频率远低于植物，这可能受性别决定系统施加的演化约束。本研究针对中亚地区古北界绿蟾蜍（Bufo viridis subgroup）的异源多倍化（allopolyploidization）起源与演化后果展开探究，该类群存在三个倍性水平以及两种不同的基因组传递模式：有性传递与无性传递，旨在达成两项研究目标：其一，解析一个包含多个近缘支系的物种辐射类群中网状系统发育的拓扑结构；其二，探究多倍化事件后可能发生的基因组重排过程。基于30个跨扩增微卫星标记的家系分析，不仅证实了异源多倍体的母本起源，还揭示了其亚基因组的父本来源与演化关系。对连锁群共线性的分析显示，共有3个标记发生了易位事件；这类易位仅发生在异源多倍体蟾蜍的父本遗传亚基因组中，且仅靶向绿蟾蜍辐射类群多个二倍体物种中负责性别决定的连锁群。二倍体与多倍体蟾蜍的重组率并无显著差异，整体而言雄性的重组率大幅降低，且这一特征不受连锁群类型与倍性水平的影响。异源三倍体蟾蜍中通过无性方式传递的亚基因组，为强烈遗传漂变现象提供了实验依据，该现象推测由重组阻滞所导致。古北界绿蟾蜍辐射类群似乎为探究多倍化与无性传递对脊椎动物基因组动态的影响提供了独一无二的研究模型。