Yamasaki Masanori, Tenaillon Maud I, Bi Irie Vroh, Schroeder Steve G, Sanchez-Villeda Hector, Doebley John F, Gaut Brandon S, McMullen Michael D
Division of Plant Sciences, University of Missouri, Columbia, Misssouri 65211, USA.
Plant Cell. 2005 Nov;17(11):2859-72. doi: 10.1105/tpc.105.037242. Epub 2005 Oct 14.
Maize (Zea mays subsp mays) was domesticated from teosinte (Z. mays subsp parviglumis) through a single domestication event in southern Mexico between 6000 and 9000 years ago. This domestication event resulted in the original maize landrace varieties, which were spread throughout the Americas by Native Americans and adapted to a wide range of environmental conditions. Starting with landraces, 20th century plant breeders selected inbred lines of maize for use in hybrid maize production. Both domestication and crop improvement involved selection of specific alleles at genes controlling key morphological and agronomic traits, resulting in reduced genetic diversity relative to unselected genes. Here, we sequenced 1095 maize genes from a sample of 14 inbred lines and chose 35 genes with zero sequence diversity as potential targets of selection. These 35 genes were then sequenced in a sample of diverse maize landraces and teosintes and tested for selection. Using two statistical tests, we identified eight candidate genes. Extended gene sequencing of these eight candidate loci confirmed that six were selected throughout the gene, and the remaining two exhibited evidence of selection in the 3' portion of each gene. The selected genes have functions consistent with agronomic selection for nutritional quality, maturity, and productivity. Our large-scale screen for artificial selection allows identification of genes of potential agronomic importance even when gene function and the phenotype of interest are unknown.
玉米（Zea mays subsp mays）是在6000至9000年前于墨西哥南部通过一次驯化事件从大刍草（Z. mays subsp parviglumis）驯化而来的。这次驯化事件产生了最初的玉米地方品种，这些品种被美洲原住民传播到整个美洲，并适应了广泛的环境条件。从地方品种开始，20世纪的植物育种家选择了玉米自交系用于杂交玉米生产。驯化和作物改良都涉及在控制关键形态和农艺性状的基因上选择特定等位基因，导致相对于未选择的基因遗传多样性降低。在这里，我们对来自14个自交系样本的1095个玉米基因进行了测序，并选择了35个序列多样性为零的基因作为潜在的选择目标。然后在不同的玉米地方品种和大刍草样本中对这35个基因进行测序并进行选择测试。使用两种统计测试，我们鉴定出了8个候选基因。对这8个候选位点进行的扩展基因测序证实，其中6个在整个基因中都受到了选择，其余2个在每个基因的3'部分表现出选择的证据。所选基因的功能与对营养品质、成熟度和生产力的农艺选择一致。我们对人工选择的大规模筛选使得即使在基因功能和感兴趣的表型未知的情况下，也能够鉴定出具有潜在农艺重要性的基因。
