Strongly asymmetric hybridization barriers shape the origin of a new polyploid species and its hybrid ancestor
Strongly asymmetric hybridization barriers shape the origin of a new polyploid species and its hybrid ancestor
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DOI：
10.3732/ajb.1500471
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发表时间：
2016-07-01
影响因子：
3
通讯作者：
Puzey, Joshua R.
中科院分区：
文献类型：
--
作者：
Vallejo-Marin, Mario;Cooley, Arielle M.;Puzey, Joshua R.
研究的前提：二倍体和四倍体之间的杂交可以导致新的异源多倍体物种，通常通过三倍体中间体。可行的三倍体通常是不对称地产生的，其中母亲的倍性比父亲的倍性高的“母系过剩”杂交的成功率更高。方法：利用二倍体(M.guttatus)和四倍体(M.luteus)后代之间的正反交，确定由父本和母本产生的三倍体Xrobertsii杂交后代的生存能力。母性过度杂交。为了研究实验结果是否能预测田间可见的模式，我们进行了亲子关系分析，比较了自然种群和其二倍体、四倍体和三倍体后代。从已有的基因组数据中获得的细胞器序列，辅以额外的基因分型，被用来建立多个斑潜蝇和xrobertsii多个群体的母系祖先。KEY结果：我们发现了斑潜蝇不对称起源的有力证据，但与常见的模式相反，父本超额杂交比母本超额杂交更成功。这些结果成功地预测了自然界中杂种的形成：114个xrobertsii个体中的111个个体和27个Peregrinus个体中的27个个体具有滴虫母体单倍型。结论：这项研究包括了首次的微藻叶绿体基因组组装，证明了通过基因组浏览进行亲子关系分析的实用性。我们强调了用实验方法补充基因组分析以了解异源多倍体物种形成中的不对称性的好处。
PREMISE OF THE STUDY: Hybridization between diploids and tetraploids can lead to new allopolyploid species, often via a triploid intermediate. Viable triploids are often produced asymmetrically, with greater success observed for "maternal-excess" crosses where the mother has a higher ploidy than the father. Here we investigated the evolutionary origins of Mimulus peregrinus, an allohexaploid recently derived from the triploid M. xrobertsii, to determine whether reproductive asymmetry has shaped the formation of this new species.METHODS: We used reciprocal crosses between the diploid (M. guttatus) and tetraploid (M. luteus) progenitors to determine the viability of triploid M. xrobertsii hybrids resulting from paternal-vs. maternal-excess crosses. To investigate whether experimental results predict patterns seen in the field, we performed parentage analyses comparing natural populations of M. peregrinus to its diploid, tetraploid, and triploid progenitors. Organellar sequences obtained from pre-existing genomic data, supplemented with additional genotyping was used to establish the maternal ancestry of multiple M. peregrinus and M. xrobertsii populations.KEY RESULTS: We found strong evidence for asymmetric origins of M. peregrinus, but opposite to the common pattern, with paternal-excess crosses significantly more successful than maternal-excess crosses. These results successfully predicted hybrid formation in nature: 111 of 114 M. xrobertsii individuals, and 27 of 27 M. peregrinus, had an M. guttatus maternal haplotype.CONCLUSION: This study, which includes the first Mimulus chloroplast genome assembly, demonstrates the utility of parentage analysis through genome skimming. We highlight the benefits of complementing genomic analyses with experimental approaches to understand asymmetry in allopolyploid speciation.