Does selection occur at the intermediate zone of two insufficiently isolated populations? A whole-genome analysis along an altitudinal gradient
Does selection occur at the intermediate zone of two insufficiently isolated populations? A whole-genome analysis along an altitudinal gradient
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DOI：
10.1007/s10265-022-01429-1
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发表时间：
2021-04
影响因子：
2.8
通讯作者：
Naofumi Yoshida;S. Morinaga;T. Wakamiya;Yuu Ishii;S. Kubota;K. Hikosaka
中科院分区：
文献类型：
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作者：
Naofumi Yoshida;S. Morinaga;T. Wakamiya;Yuu Ishii;S. Kubota;K. Hikosaka
适应性分化甚至发生在不充分隔离的种群之间，当它们的栖息地之间的环境有很大差异时。个体存在于两个不同的人群的中间地带，预计有一个混合的遗传结构，由于基因流。作用于遗传混合个体的选择压力可能限制基因流动，维持适应性分化。在这里，我们解决了一个问题，选择是否发生在两个不同的群体之间的遗传混合个体。伊吹，日本中部。我们获得了沿着359- 1，317 m海拔梯度的拟南芥植物的全基因组序列，具有高空间分辨率（平均海拔间隔为20 m）。我们发现了一个高地和低地基因混合的区域（中间亚群）。在中间亚群中，我们确定了5个和13个基因组区域，其中包括3个和8个基因，分别在高地和低地亚群中积累了高频率的等位基因。此外，我们还发现，这些选择的基因组区域的高地等位基因的频率在低的低地亚群相比，非选择的区域。这些结果表明，在中间亚群中的选择可能限制了基因流，并有助于海拔之间的适应性分歧。我们还确定了7个基因组区域，在中间亚群中杂合子频率低。我们的结论是，不同类型的选择，除了基因流发生在中间海拔高度和形状的遗传结构跨越海拔。
Adaptive divergence occurs even between insufficiently isolated populations when there is a great difference in environments between their habitats. Individuals present in an intermediate zone of the two divergent populations are expected to have an admixed genetic structure due to gene flow. A selective pressure that acts on the genetically admixed individuals may limit the gene flow and maintain the adaptive divergence. Here, we addressed a question whether selection occurs in the genetically admixed individuals between two divergent populations.Arabidopsis halleriis a perennial montane plant, which has clear phenotypic dimorphisms between highland and lowland habitats in Mt. Ibuki, central Japan. We obtained the whole-genome sequences ofArabidopsis halleriplants along an altitudinal gradient of 359–1,317 m with a high spatial resolution (mean altitudinal interval of 20 m). We found a zone where the highland and lowland genes were mixing (intermediate subpopulation). In the intermediate subpopulation, we identified 5 and 13 genome regions, which included 3 and 8 genes, that had a high frequency of alleles that are accumulated in highland and lowland subpopulations, respectively. In addition, we also found that the frequency of highland alleles of these selected genome regions was smaller in the lowland subpopulation compared with that of the non-selected regions. These results suggest that the selection in the intermediate subpopulation might limit the gene flow and contribute to the adaptive divergence between altitudes. We also identified 7 genome regions that had low heterozygote frequencies in the intermediate subpopulation. We conclude that different types of selection in addition to gene flow occur at the intermediate altitude and shape the genetic structure across altitudes.