State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center of China, MOA Key Laboratory of Maize Biology, China Agricultural University, Beijing, 100193, China.
Joint International Research Laboratory of Crop Molecular Breeding, China Agricultural University, Beijing, 100193, China.
BMC Plant Biol. 2022 Feb 18;22(1):72. doi: 10.1186/s12870-022-03427-w.
Maize (Zea mays L. ssp. mays) was domesticated from teosinte (Zea mays ssp. parviglumis) about 9000 years ago in southwestern Mexico and adapted to a range of environments worldwide. Researchers have depicted the maize domestication and adaptation processes over the past two decades, but efforts have been limited either in sample size or genetic diversity. To better understand these processes, we conducted a genome-wide survey of 982 maize inbred lines and 190 teosinte accessions using over 40,000 single-nucleotide polymorphism markers.
Population structure, principal component analysis, and phylogenetic trees all confirmed the evolutionary relationship between maize and teosinte, and determined the evolutionary lineage of all species within teosinte. Shared haplotype analysis showed similar levels of ancestral alleles from Zea mays ssp. parviglumis and Zea mays ssp. mexicana in maize. Scans for selection signatures identified 394 domestication sweeps by comparing wild and cultivated maize and 360 adaptation sweeps by comparing tropical and temperate maize. Permutation tests revealed that the public association signals for flowering time were highly enriched in the domestication and adaptation sweeps. Genome-wide association study identified 125 loci significantly associated with flowering-time traits, ten of which identified candidate genes that have undergone selection during maize adaptation.
In this study, we characterized the history of maize domestication and adaptation at the population genomic level and identified hundreds of domestication and adaptation sweeps. This study extends the molecular mechanism of maize domestication and adaptation, and provides resources for basic research and genetic improvement in maize.
玉米（Zea mays L. ssp. mays）约 9000 年前由墨西哥西南部的类蜀黍（Zea mays ssp. parviglumis）驯化而来，并适应了世界各地的各种环境。研究人员在过去二十年中描绘了玉米的驯化和适应过程，但这些努力要么在样本量上，要么在遗传多样性上受到限制。为了更好地理解这些过程，我们使用超过 40000 个单核苷酸多态性标记对 982 个玉米自交系和 190 个类蜀黍进行了全基因组调查。
群体结构、主成分分析和系统发育树都证实了玉米和类蜀黍之间的进化关系，并确定了类蜀黍中所有物种的进化谱系。共享单倍型分析表明，玉米中来自 Zea mays ssp. parviglumis 和 Zea mays ssp. mexicana 的祖先等位基因水平相似。通过比较野生和栽培玉米，扫描选择信号鉴定了 394 个驯化 sweeps，通过比较热带和温带玉米，扫描选择信号鉴定了 360 个适应 sweeps。置换检验显示，开花时间的公共关联信号在驯化和适应 sweeps 中高度富集。全基因组关联研究鉴定出 125 个与开花时间性状显著相关的位点，其中 10 个鉴定出在玉米适应过程中经历选择的候选基因。
在这项研究中，我们在群体基因组水平上描述了玉米驯化和适应的历史，并鉴定了数百个驯化和适应 sweeps。这项研究扩展了玉米驯化和适应的分子机制，并为玉米的基础研究和遗传改良提供了资源。
