串联重复序列在籼粳亚种间的差异及其与栽培稻遗传分化关系的研究

以中籼稻南京11号(N11)和粳稻巴利拉(Balilla)杂交F1代的DH群体为材料，利用荧光原位杂交技术(FISH)结合程氏指数分类，分析2个串联重复序列Os48、45S rDNA在DH群体中的分布，探讨串联重复序列在栽培稻籼、粳亚种间的差异及其与栽培稻遗传分化的关系。结果表明：串联重复序列45S rDNA在DH群体中的分布具有明显的籼、粳特异性；Os48在DH群体中的分布趋势与程氏指数的分类结果一致，而杂交信号为2对的6个DH株系都表现为粳型，利用减数分裂的粗线期染色体进行分析，这6个株系的Os48所在染色体均为第5、6号。从本研究结果可知，串联重复序列Os48、45S rDNA与栽培稻遗传分化有较密切的关系，可作为研究籼、粳分化的标记。

Investigation on the Relationship between the Distribution of Tandemly Repeated Sequences and the Differentiation of Rice Subspecies Indica and Japonica

In order to study the relationships between the distribution of two tandemly repeated sequences, Os48 and 45S rDNA, and the differentiation of indica and japonica subspecies, the FISH (fluorescence in situ hybridization) technique was applied to detect fluorescent signals on both pachytene and (early) metaphase chromosomes. Chromosomes were prepared from the DH population derived from the F1individuals of a cross between Nil (subsp. indica) and balilla (subsp. japonica). Karyotype analysis showed that all the six DH lines carrying only two pairs of Os48 signals were japonica in which one signal was on pachytene chromosomes 5L and the other one on 6L. On the other hand, most DH lines with 7 or 8 Os48 signals were indica or indica cline type. The results showed that the distribution of Os48 was consistent with the classification using Cheng's systematic index, while that of 45S rDNA signals on (early) metaphase chromosomes among DH lines evidently displayed the subspecies-specific characteristics. Our studies indicated that tandemly repeated sequences Os48 and 45S rDNA played an important role on genetic differentiation of cultivated rice, and they could be applied as molecular markers in analytical study on rice evolution.