A population genetic model to infer allotetraploid speciation and long-term evolution applied to two yarrow species
A population genetic model to infer allotetraploid speciation and long-term evolution applied to two yarrow species
复制标题
推断异源四倍体物种形成和长期进化的群体遗传模型应用于两个西洋蓍草物种
DOI：
10.1111/nph.12262
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发表时间：
2013-07-01
期刊：
影响因子：
9.4
通讯作者：
Vogl, Claus
中科院分区：
文献类型：
--
作者：
Guo, Yan-Ping;Tong, Xiao-Yuan;Vogl, Claus
异源四倍体物种形成，即从两个二倍体物种产生一个杂交的四倍体物种，以及四倍体种群和物种的长期进化在植物中是重要的。我们建立了一个群体遗传模型，用于从祖先和后代物种的数据中推断四倍体群体的群体遗传参数。通过异源四倍化，从二倍体后代Achilea alpina-2x和A.asiatica-2x中获得了两个种：Achilea alpina-4x和A.wilsoniana-4x。然而，种群遗传过程还没有得到详细的研究。我们将该模型应用于四个种的种群中的三个核基因的序列，并将它们的变异模式与四个叶绿体区域的变异模式进行了比较。质体数据表明，这两个四倍体物种可能起源于多次独立的异源多倍化事件，并自那以来积累了许多突变。利用核数据，我们发现同源重组或基因转换的比率很低，相对于两个二倍体物种的结合水平，多样性有所降低。目前用一个新的概率模型进行的分析表明，在四倍体物种形成过程中存在遗传瓶颈，这两个四倍体物种具有很长的进化历史，并且它们在同源基因组之间存在少量的遗传交换。
Allotetraploid speciation, that is, the generation of a hybrid tetraploid species from two diploid species, and the long-term evolution of tetraploid populations and species are important in plants. We developed a population genetic model to infer population genetic parameters of tetraploid populations from data of the progenitor and descendant species. Two yarrow species, Achillea alpina-4x and A.wilsoniana-4x, arose by allotetraploidization from the diploid progenitors, A.acuminata-2x and A.asiatica-2x. Yet, the population genetic process has not been studied in detail. We applied the model to sequences of three nuclear genes in populations of the four yarrow species and compared their pattern of variability with that in four plastid regions. The plastid data indicated that the two tetraploid species probably originated from multiple independent allopolyploidization events and have accumulated many mutations since. With the nuclear data, we found a low rate of homeologous recombination or gene conversion and a reduction in diversity relative to the level of both diploid species combined. The present analysis with a novel probabilistic model suggests a genetic bottleneck during tetraploid speciation, that the two tetraploid species have a long evolutionary history, and that they have a small amount of genetic exchange between the homeologous genomes.