Conditional neutrality at two adjacent NBS-LRR disease resistance loci in natural populations of Arabidopsis lyrata
Conditional neutrality at two adjacent NBS-LRR disease resistance loci in natural populations of Arabidopsis lyrata
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DOI：
10.1111/j.1365-294x.2008.03968.x
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发表时间：
2008-12-01
影响因子：
4.9
通讯作者：
Wright, Stephen I.
中科院分区：
文献类型：
--
作者：
Gos, Gesseca;Wright, Stephen I.
我们检查了异交植物拟南芥种群中包含两个连锁候选抗病性（NBS-LRR）基因的基因组区域的核苷酸多样性模式。与整个基因组中的两个相邻对照基因和中性参考基因相比，NBS-LRR基因表现出升高的非同义变异和大量导致早期终止密码子和/或移码突变的主效应多态性。相比之下，对同义多样性的分析没有提供任何证据表明该地区在所调查的七个人群中受到长期平衡选择或最近的选择性扫描。此外，与早期对这些 R 基因之一的调查相反，没有证据表明抗性基因或主要效应突变会导致群体之间的分化加剧。我们认为，在某些情况下，在不存在相应病原体的情况下，条件中性，而不是长期平衡选择或局部适应，可能是 R 基因功能多态性升高的重要原因。与 R 基因相反，对侧翼 FERONIA 基因座的多样性和分化分析显示出较高的群体差异，表明该基因座在受精过程中控制雄性-雌性信号传导的局部适应。
We examined patterns of nucleotide diversity at a genomic region containing two linked candidate disease resistance (NBS-LRR) genes in seven populations of the outcrossing plant Arabidopsis lyrata. In comparison with two adjacent control genes and neutral reference genes across the genome, the NBS-LRR genes exhibited elevated nonsynonymous variation and a large number of major-effect polymorphisms causing early stop codons and/or frameshift mutations. In contrast, analysis of synonymous diversity provided no evidence that the region was subject to long-term balancing selection or recent selective sweeps in any of the seven populations surveyed. Also in contrast with earlier surveys of one of these R genes, there was no evidence that the resistance genes or the major-effect mutations were subject to elevated differentiation between populations. We suggest that conditional neutrality in the absence of the corresponding pathogen, rather than long-term balancing selection or local adaptation, may in some circumstances be a significant cause of elevated functional polymorphism at R genes. In contrast with the R genes, analysis of diversity and differentiation at the flanking FERONIA locus showed high population divergence, suggesting local adaptation on this locus controlling male-female signalling during fertilization.