Identifying loci under selection across contrasting environments in Avena barbata using quantitative trait locus mapping
Identifying loci under selection across contrasting environments in Avena barbata using quantitative trait locus mapping
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DOI：
10.1111/j.1365-294x.2005.02835.x
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发表时间：
2006-04-01
影响因子：
4.9
通讯作者：
Latta, RG
中科院分区：
文献类型：
--
作者：
Gardner, KM;Latta, RG
在不同的湿度环境下，我们构建了一种天然存在的草甘树（Avena barbata, Pott ex Link）、禾科植物生态型杂交的重组自交系。这些品系每两年在两个对照的大田进行普通园林互栽试验，并在一个新的、良性的温室环境中进行适应性评估。129个标记的AFLP（扩增片段长度多态性）连锁图谱在19个连锁组中跨越644 cM，比预期的更小，连锁组更多。因此，部分巴巴塔古猿基因组仍未被绘制，可能是因为它们在生态型之间缺乏差异。尽管如此，我们还是在自然环境和温室环境中发现了QTL（数量性状位点）。多年来，在同一地点，相同的基因座仍然在选择相同的等位基因。在不同的位点上，一组重叠的基因座被选择，要么(i)在两个位点上都有相同的等位基因，要么（ii）在一个位点上被选择，而在另一个位点上被选择。温室选择下的QTL通常与田间选择下的QTL不相关，因为选择作用于不同的性状。我们发现很少有证据表明选择倾向于交替环境中的交替等位基因，如果基因型-环境相互作用要维持芭蕉的遗传变异，这是必要的。在遗传力最高的温室环境中，加性效应QTL最能解释重组自交系间的遗传变异，而且过去的选择并未消除变异。
We constructed recombinant inbred lines of a cross between naturally occurring ecotypes of Avena barbata (Pott ex Link), Poaceae, associated with contrasting moisture environments. These lines were assessed for fitness in common garden reciprocal transplant experiments in two contrasting field sites in each of two years, as well as a novel, benign greenhouse environment. An AFLP (amplified fragment length polymorphism) linkage map of 129 markers spanned 644 cM in 19 linkage groups, which is smaller, with more linkage groups, than expected. Therefore parts of the A. barbata genome remain unmapped, possibly because they lack variation between the ecotypes. Nevertheless, we identified QTL (quantitative trait loci) under selection in both native environments and in the greenhouse. Across years at the same site, the same loci remain under selection, for the same alleles. Across sites, an overlapping set of loci are under selection with either (i) the same alleles favoured at both sites or (ii) loci under selection at one site and neutral at the other. QTL under selection in the greenhouse were generally unlinked to those under selection in the field because selection acted on a different trait. We found little evidence that selection favours alternate alleles in alternate environments, which would be necessary if genotype by environment interaction were to maintain genetic variation in A. barbata. Additive effect QTL were best able to explain the genetic variation among recombinant inbred lines for the greenhouse environment where heritability was highest, and past selection had not eliminated variation.