Supplementary Material for: Diversity of Chromosomal Karyotypes in Maize and Its Relatives

Maize is a highly diverse species on the gene sequence level. With the recent development of methods to distinguish each of the 10 pairs of homologues in somatic root tip spreads, a wide collection of maize lines was subjected to karyotype analysis to serve as a reference for the community and to examine the spectrum of chromosomal features in the species. The core nested association mapping progenitor collection and additional selections of diversity lines were examined. Commonly used inbred lines were included in the analysis. The centromere 4 specific repeat and ribosomal RNA loci were invariant. The CentC centromere repeat exhibited extensive differences in quantity on any particular chromosome across lines. Knob heterochromatin was highly variable with locations at many sites in the genome. Lastly, representative examples from other species in the genus <i>Zea</i> (teosintes) were examined, which provide information on the evolution of chromosomal features.

玉米是一类在基因序列水平上具有高度多样性的物种。随着近期开发出可区分体细胞根尖染色体铺片内10对同源染色体每条染色体的方法，研究团队对大规模玉米品系集合开展核型分析，以期为学界提供参考，并解析该物种的染色体特征谱。本次分析涵盖了核心嵌套关联作图（Nested Association Mapping）亲本集合、额外筛选的多样性品系，同时纳入了常用玉米自交系。第4号染色体着丝粒特异性重复序列与核糖体RNA基因座均表现为保守不变。CentC着丝粒重复序列在不同品系的同一染色体上的拷贝数存在显著差异。结节异染色质则表现出高度多态性，其在基因组内的分布位点遍布多处。最后，研究团队还对玉蜀黍属（Zea）其他物种的代表性样本（大刍草）进行了分析，这些结果为染色体特征的演化研究提供了重要依据。