Population Genomics of the Arabidopsis thaliana Flowering Time Gene Network
Population Genomics of the Arabidopsis thaliana Flowering Time Gene Network
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DOI：
10.1093/molbev/msp161
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发表时间：
2009-11-01
影响因子：
10.7
通讯作者：
Purugganan, Michael D.
中科院分区：
文献类型：
--
作者：
Flowers, Jonathan M.;Hanzawa, Yoshie;Purugganan, Michael D.
开花时间是模式植物拟南芥生活史策略的关键组成部分，其在基因型之间存在数量上的差异。进化和生态遗传学的一个重要问题是了解自然选择如何作用于这种具有重要生态意义的性状。在这里，我们对开花时间网络中 52 个基因的数据进行了重新测序数据的群体基因组研究。 McDonald-Kreitman 中性测试表明，跨位点汇集时氨基酸多态性严重过量。整个开花时间网络中过量的替换多态性以及相对于同义变化的替换和非编码多态性向稀有等位基因倾斜的衍生频谱与这些基因中分离的一大类有害多态性是一致的。假设同义变化具有选择性中性，我们估计大约 30% 的氨基酸多态性是有害的。在我们的分析中，适应性替代的证据并不那么突出。光周期调节基因 CO 和赤霉酸转录因子 AtMYB33 显示了氨基酸突变适应性固定的证据。对延长单倍型的测试显示，没有任何开花时间等位基因的例子，其单倍型的长度与先前报道的无效 fri(col) 等位基因相关的长度相当。这表明 FRI 基因可能在此考虑的开花时间基因中具有独特的强烈或最近的选择历史。尽管有一些证据表明这些生活史基因存在适应性进化，但似乎稍微有害的多态性是拟南芥开花时间网络中自然分子变异的主要组成部分。
The time to flowering is a key component of the life-history strategy of the model plant Arabidopsis thaliana that varies quantitatively among genotypes. A significant problem for evolutionary and ecological genetics is to understand how natural selection may operate on this ecologically significant trait. Here, we conduct a Population genomic Study Of resequencing data from 52 genes in the flowering time network. McDonald-Kreitman tests of neutrality suggested a strong excess of amino acid polymorphism when pooling across loci. This excess of replacement polymorphism across the flowering time network and a skewed derived frequency spectrum toward rare alleles for both replacement and noncoding polymorphisms relative to synonymous changes is consistent with a large class of deleterious polymorphisms segregating in these genes. Assuming selective neutrality of synonymous changes, we estimate that approximately 30% of amino acid polymorphisms are deleterious. Evidence of adaptive Substitution is less prominent ill Our analysis. The photoperiod regulatory gene, CO, and a gibberellic acid transcription factor, AtMYB33, show evidence of adaptive fixation of amino acid mutations. A test for extended haplotypes revealed no examples of flowering time alleles with haplotypes comparable ill length to those associated with the null fri(col) allele reported previously. This suggests that the FRI gene likely has it uniquely intense or recent history of selection among the flowering time genes considered here. Although there is some evidence for adaptive evolution in these life-history genes, it appears that slightly deleterious polymorphisms are a major component Of natural Molecular variation in the flowering time network of A. thaliana.