Megabase-Scale Inversion Polymorphism in the Wild Ancestor of Maize
Megabase-Scale Inversion Polymorphism in the Wild Ancestor of Maize
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DOI：
10.1534/genetics.112.138578
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发表时间：
2012-07-01
期刊：
影响因子：
3.3
通讯作者：
Ross-Ibarra, Jeffrey
中科院分区：
文献类型：
--
作者：
Fang, Zhou;Pyhajarvi, Tanja;Ross-Ibarra, Jeffrey
染色体倒位被认为在局部适应中发挥特殊作用，通过显著抑制重组，有利于维持局部适应的等位基因。然而，相对较少的倒位已在人口基因组数据的特点。基于单核苷酸多态性（SNP）基因分型在一个大面板的玉米，我们已经确定了一个类似的50 Mb的区域上的短臂1号染色体的多态性模式是高度一致的多态性着丝粒倒位，捕获> 700个基因。与玉米属和摩擦草属的其他分类群相比，衍生的倒置状态仅存在于野生Z中。玉米的亚种parviglumis和mexicana，并且在驯化的玉米中完全不存在。多态性的模式表明，倒置是古老的，地理上广泛的小颖。细胞学筛选几乎没有发现倒位环的证据，这表明倒位杂合子可能会遭受一些交叉诱导的健身后果。倒位多态性显示了适应性进化的证据，包括强烈的海拔梯度，与环境变量和表型性状的统计关联，以及倒位等位基因的偏斜单倍型频谱。
Chromosomal inversions are thought to play a special role in local adaptation, through dramatic suppression of recombination, which favors the maintenance of locally adapted alleles. However, relatively few inversions have been characterized in population genomic data. On the basis of single-nucleotide polymorphism (SNP) genotyping across a large panel of Zea mays, we have identified an similar to 50-Mb region on the short arm of chromosome 1 where patterns of polymorphism are highly consistent with a polymorphic paracentric inversion that captures >700 genes. Comparison to other taxa in Zea and Tripsacum suggests that the derived, inverted state is present only in the wild Z. mays subspecies parviglumis and mexicana and is completely absent in domesticated maize. Patterns of polymorphism suggest that the inversion is ancient and geographically widespread in parviglumis. Cytological screens find little evidence for inversion loops, suggesting that inversion heterozygotes may suffer few crossover-induced fitness consequences. The inversion polymorphism shows evidence of adaptive evolution, including a strong altitudinal cline, a statistical association with environmental variables and phenotypic traits, and a skewed haplotype frequency spectrum for inverted alleles.