An Analysis of Genetic Diversity Across the Maize Genome Using Microsatellites
An Analysis of Genetic Diversity Across the Maize Genome Using Microsatellites
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DOI：
10.1534/genetics.104.032086
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发表时间：
2005-03
期刊：
影响因子：
3.3
通讯作者：
Y. Vigouroux;S. Mitchell;Y. Matsuoka;M. Hamblin;S. Kresovich;J. S. Smith;Jennifer S. Jaqueth;O. Smith-O.
中科院分区：
文献类型：
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作者：
Y. Vigouroux;S. Mitchell;Y. Matsuoka;M. Hamblin;S. Kresovich;J. S. Smith;Jennifer S. Jaqueth;O. Smith-O.
驯化瓶颈和人工选择如何塑造现代作物基因组中遗传变异的数量和分布，人们知之甚少。我们分析了分布在玉米基因组中的462个简单重复序列（SSRs）或微卫星的多样性，并将这些SSRs的多样性与其野生祖先大刍草的多样性进行了比较。结果显示玉米相对于大刍草存在适度的全基因组多样性缺陷。具有二核苷酸重复基序的SSRs的多样性相对缺陷小于具有两个以上重复基序的SSRs，这表明具有较高突变率的SSRs已经部分从驯化瓶颈中恢复过来。我们分析了SSR多样性与驯化性状QTL接近度之间的关系，发现二者之间没有关系。然而，我们确实观察到，在相距2 cM以内的SSR之间，多样性统计数据存在微弱但显著的空间相关性，这表明SSR多样性在整个基因组中的格局很弱。462个ssr中有24个（5%）在多次试验中显示出玉米正选择的证据。总体而言，玉米ssr遗传多样性模式主要可以用瓶颈效应来解释，选择效应较小。
How domestication bottlenecks and artificial selection shaped the amount and distribution of genetic variation in the genomes of modern crops is poorly understood. We analyzed diversity at 462 simple sequence repeats (SSRs) or microsatellites spread throughout the maize genome and compared the diversity observed at these SSRs in maize to that observed in its wild progenitor, teosinte. The results reveal a modest genome-wide deficit of diversity in maize relative to teosinte. The relative deficit of diversity is less for SSRs with dinucleotide repeat motifs than for SSRs with repeat motifs of more than two nucleotides, suggesting that the former with their higher mutation rate have partially recovered from the domestication bottleneck. We analyzed the relationship between SSR diversity and proximity to QTL for domestication traits and observed no relationship between these factors. However, we did observe a weak, although significant, spatial correlation for diversity statistics among SSRs within 2 cM of one another, suggesting that SSR diversity is weakly patterned across the genome. Twenty-four of 462 SSRs (5%) show some evidence of positive selection in maize under multiple tests. Overall, the pattern of genetic diversity at maize SSRs can be explained largely by a bottleneck effect with a smaller effect from selection.