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利用组成玉米异染色质纽的180-bp重复序列和TR-1元件以及45SrDNA对二倍体多年生类玉米(ZeadiploperennisIltisDoebtey,DP)、玉米自交系F102及其远缘杂交后代的有丝分裂中期染色体进行了定位.在DP中,第1和4染色体的短臂以及第4和5染色体的长臂上的异染色质纽只有180-bp重复序列信号,此外,在第2和5染色体的短臂以及第2,6,7,8和9染色体的长臂同时检测到180-bp重复序列和TR-1的信号.在玉米自交系F102中,180-bp重复序列信号出现在第7染色体短臂和第8染色体一个成员的长臂,TR-1信号是在第6染色体的随体上,该玉米自交系中没有观察到双重复序列同时出现的现象.两物种间,180-bp重复序列和TR-1元件信号大小、数目和染色体分布存在多态性,同一种内部分同源染色体之间具有异态性.以这些细胞学标记为探针,玉米和DP种间杂交后代得以鉴定.180-bp重复序列和TR-1元件比较定位分析有助于了解玉米属基因组间的结构和进化关系.
The mitotic metaphase chromosomes of diploid perennial maize (Zea matellisItis Doebtey, DP), maize inbred line F102 and its distant hybridization progeny were amplified using 180-bp repeats and TR-1 elements and 45S rDNA, which constitute heterochromatin of maize, In DP, the short arms of chromosomes 1 and 4 and the heterochromatic knobs of the long arms of chromosomes 4 and 5 have only a 180-bp repeat signal. In addition, the short arm of chromosomes 2 and 5, The 180-bp repeat and the TR-1 signal were detected simultaneously in the long arms of chromosomes 2, 6, 7, 8 and 9. In the maize inbred line F102, the 180-bp repeat signal appeared on the short arm of chromosome 7 and The TR-1 signal on the long arm of one member of chromosome 8 was observed on the chromosome of chromosome 6 and no double duplication was observed in the maize inbred line. The 180-bp repeats The size, number and chromosomal distribution of TR-1 elements were polymorphic and heterochromic within the same internal homologous chromosomes. Using these cytological markers as probes, crosses between maize and DP were identified.180 The -bp repeats and the TR-1 element alignment analysis helped Structure and evolutionary relationships among the genomes of the genus.