Laboratory of Genetics, The University of Wisconsin-Madison, Madison, WI.
USDA-ARS Plant Genetics Research Unit, Columbia, MO.
J Hered. 2018 Mar 16;109(3):333-338. doi: 10.1093/jhered/esx073.
Genomic scans for genes that show the signature of past selection have been widely applied to a number of species and have identified a large number of selection candidate genes. In cultivated maize (Zea mays ssp. mays) selection scans have identified several hundred candidate domestication genes by comparing nucleotide diversity and differentiation between maize and its progenitor, teosinte (Z. mays ssp. parviglumis). One of these is a gene called zea agamous-like1 (zagl1), a MADS-box transcription factor, that is known for its function in the control of flowering time. To determine the trait(s) controlled by zagl1 that was (were) the target(s) of selection during maize domestication, we created a set of recombinant chromosome isogenic lines that differ for the maize versus teosinte alleles of zagl1 and which carry cross-overs between zagl1 and its neighbor genes. These lines were grown in a randomized trial and scored for flowering time and domestication related traits. The results indicated that the maize versus teosinte alleles of zagl1 affect flowering time as expected, as well as multiple traits related to ear size with the maize allele conferring larger ears with more kernels. Our results suggest that zagl1 may have been under selection during domestication to increase the size of the maize ear.
基因组扫描用于寻找具有过去选择特征的基因已广泛应用于许多物种，并确定了大量的候选选择基因。在栽培玉米（Zea mays ssp. mays）中，通过比较玉米与其祖先类蜀黍（Z. mays ssp. parviglumis）之间的核苷酸多样性和分化，选择扫描鉴定了数百个候选驯化基因。其中一个基因叫做玉米同源异型盒转录因子 1（zea agamous-like1，zagl1），它以控制开花时间的功能而闻名。为了确定 zagl1 控制的性状是玉米驯化过程中选择的目标，我们创建了一组重组染色体同基因系，这些同基因系在玉米与类蜀黍 zagl1 等位基因之间存在差异，并在 zagl1 与其相邻基因之间发生交叉。这些系在随机试验中生长，并对开花时间和驯化相关性状进行评分。结果表明，zagl1 的玉米与类蜀黍等位基因如预期的那样影响开花时间，以及与穗大小相关的多个性状，玉米等位基因赋予更大的穗和更多的穗粒。我们的结果表明，zagl1 可能在驯化过程中受到选择，以增加玉米穗的大小。
