Selection on Meiosis Genes in Diploid and Tetraploid Arabidopsis arenosa
Selection on Meiosis Genes in Diploid and Tetraploid Arabidopsis arenosa
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DOI：
10.1093/molbev/msu398
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发表时间：
2015-04-01
影响因子：
10.7
通讯作者：
Bomblies, Kirsten
中科院分区：
文献类型：
--
作者：
Wright, Kevin M.;Arnold, Brian;Bomblies, Kirsten
减数分裂染色体分离对于真核生物的生育力至关重要，并且核心减数分裂过程即使在界之间也很保守。然而，最近的动物研究表明，至少有一些减数分裂基因是高度多样性或强烈分化的种群之间。是什么推动了这一点在很大程度上仍然是未知的。我们以前表明，同源四倍体Arabidopsis arenosa进化稳定的减数分裂，可能是通过降低交换率，与此相关的是强有力的证据，在已知影响轴形成，突触和交换频率的减数分裂基因的子集的选择。在这里，我们使用全基因组数据来研究70个减数分裂基因的分子进化，在更广泛的样本A。arenosa。我们采样的多倍体谱系，从喀尔巴阡山脉的二倍体谱系，和一个更远的相关二倍体谱系从相邻的，但地理上不同的潘诺尼亚盆地。我们发现，选择不仅作用于多倍体谱系中的减数分裂基因，而且还独立地作用于潘诺尼亚二倍体中减数分裂基因的一个较小的子集。在这些不同的背景下，功能相关的基因被选择靶向，在两种情况下，独立的扫描发生在相同的基因座。四倍体谱系在更多基因上具有持续的选择，每个基因中具有更多的氨基酸变化，并且这些更经常地影响保守的或潜在的功能位点。我们推测Pannonian二倍体和四倍体A. arenosa经历了介导姐妹染色单体凝聚、减数分裂染色体轴的形成和突触的结构蛋白的选择，可能是出于不同的潜在原因。
Meiotic chromosome segregation is critical for fertility across eukaryotes, and core meiotic processes are well conserved even between kingdoms. Nevertheless, recent work in animals has shown that at least some meiosis genes are highly diverse or strongly differentiated among populations. What drives this remains largely unknown. We previously showed that autotetraploid Arabidopsis arenosa evolved stable meiosis, likely through reduced crossover rates, and that associated with this there is strong evidence for selection in a subset of meiosis genes known to affect axis formation, synapsis, and crossover frequency. Here, we use genome-wide data to study the molecular evolution of 70 meiosis genes in a much wider sample of A. arenosa. We sample the polyploid lineage, a diploid lineage from the Carpathian Mountains, and a more distantly related diploid lineage from the adjacent, but biogeographically distinct Pannonian Basin. We find that not only did selection act on meiosis genes in the polyploid lineage but also independently on a smaller subset of meiosis genes in Pannonian diploids. Functionally related genes are targeted by selection in these distinct contexts, and in two cases, independent sweeps occurred in the same loci. The tetraploid lineage has sustained selection on more genes, has more amino acid changes in each, and these more often affect conserved or potentially functional sites. We hypothesize that Pannonian diploid and tetraploid A. arenosa experienced selection on structural proteins that mediate sister chromatid cohesion, the formation of meiotic chromosome axes, and synapsis, likely for different underlying reasons.