Data from: Defining the role of the MADS-box gene, Zea agamous like1, a target of selection during maize domestication

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, and 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.针对携带过往选择信号的基因开展的基因组扫描（genomic scan）已被广泛应用于诸多物种，并已鉴定出大量选择候选基因。在栽培玉米（Zea mays ssp. mays）中，研究人员通过比较玉米与其祖先大刍草（Zea mays ssp. parviglumis）之间的核苷酸多样性与群体分化程度，经基因组扫描已鉴定出数百个驯化候选基因。其中一个基因为玉米AGAMOUS类似基因1（zea agamous-like1，简称zagl1），属于MADS-box转录因子（MADS-box transcription factor），已知其功能为调控开花时间。为明确在玉米驯化过程中，zagl1所调控的性状中哪些曾作为选择靶标，我们构建了一组携带玉米与大刍草zagl1等位基因，且在zagl1及其侧翼基因间存在重组交换的重组染色体近等基因系（recombinant chromosome isogenic line）。将这些近等基因系开展随机区组种植试验，并对开花时间及驯化相关性状进行表型鉴定。试验结果表明，玉米与大刍草的zagl1等位基因确实如预期般影响开花时间；同时二者还调控多个与穗部性状相关的表型，其中玉米等位基因可使果穗更大、籽粒数目更多。本研究结果提示，在玉米驯化过程中，zagl1可能因参与增大玉米果穗而受到选择作用。