Plant Pathology Department, University of Florida, 32611, Gainesville, FL, USA.
Plant Mol Biol. 1983 Jul;2(4):177-87. doi: 10.1007/BF01578377.
Genomic variation in S1 and S2 homologous sequences, defined as the S regions, were examined in mitochondrial DNAs of 12 normal cytoplasm maize lines collected in the United States. Three genomic variants were detected among the 12 cytoplasms, eight of which were identical to the Wf9 model structure. Hybridization data with S1 and S2 DNAs and with two cosmids spanning these regions were consistent with the concept that S1 and S2 sequences are found in each normal cytoplasm. Three variations of the S1 region were established; the Wf9 structure, a second group consisting of F6, A188, and W182BN, and a third, Black Mexican. Genome structure was conserved through the S2 region in all lines examined. None of the cytoplasms included complete copies of S1; the 1400 bp repeat characteristic of S1 and S2 was absent in the S1 region of all lines. A 2.1 kb linear DNA was observed instead of a 2.3 kb DNA in F6, A188, and W182BN. Integrated copies of S1 and S2 sequences may be a constituitive characteristic of normal, male-fertile maize cytoplasms.
在美国收集的 12 种正常细胞质玉米品系的线粒体 DNA 中，研究了 S1 和 S2 同源序列（定义为 S 区）的基因组变异。在这 12 种细胞质中检测到 3 种基因组变异，其中 8 种与 Wf9 模型结构相同。与 S1 和 S2 DNA 以及跨越这些区域的两个 cosmids 的杂交数据与 S1 和 S2 序列存在于每种正常细胞质中的概念一致。确定了 S1 区域的 3 种变异；Wf9 结构、由 F6、A188 和 W182BN 组成的第二组和第三组，即黑墨西哥。在所检查的所有品系中，S2 区域的基因组结构都保持保守。没有一种细胞质包含完整的 S1 拷贝；所有品系的 S1 区域都缺乏 S1 和 S2 的 1400bp 重复特征。相反，在 F6、A188 和 W182BN 中观察到 2.1kb 的线性 DNA，而不是 2.3kb 的 DNA。S1 和 S2 序列的整合拷贝可能是正常、雄性可育玉米细胞质的组成特征。
