用覆盖抗褐飞虱基因Bph15的两个BAC克隆，即20M14 (27 kb)和64O9 (36 kb)作为探针，对非洲栽培稻、药用野生稻和宽叶野生稻体细胞染色体进行荧光原位杂交(FISH)。两个BAC克隆均被定位于非洲栽培稻和药用野生稻第4染色体的短臂上，杂交信号的百分距离分别为37.03±4.11和81.22±3.62，相应的信号检出率为41.18%和38.22%。在宽叶野生稻中，有两对同源染色体同时检出信号，分别定位于染色体的短臂和着丝粒区，信号距着丝粒平均百分距离分别为87.78±5.23和0，信号检出率为52.58%。由此推知，这两个BAC克隆在非洲栽培稻和药用野生稻的第4染色体分布同线且同区，并且在宽叶野生稻的DD基因组也存在Bph15基因的同源序列。在未封阻的情况下，BAC克隆在非洲栽培稻的多条染色体上有杂交信号，表明它和栽培稻C0t-1 DNA在一定程度上具有同源性。上述结果初步显示Bph15在3个稻种染色体中的相对位置。文章讨论了Bph15在3个种间的关系，为有效分离和利用Bph15基因提供了有益的依据，对不同基因组及二倍体和四倍体中功能基因可能进化机制的分析提供了线索。
A fluorescence in situ hybridization (FISH) procedure was adopted to physical mapping two BAC clones 20M14 (27 kb) and 64O9 (36 kb) which linked to the brown planthopper resistance gene Bph15, in O. glaberrima Steud., O. officinalis Wall, and O. latifolia Desv. The results showed that 20M14 and 64O9 were both located on the short arm of chromosome 4 in O. officinalis and O. glaberrima. The percentage distances from the centromere to hybridization sites were 37.03±4.11 and 81.22±3.62, the detection rates were 41.18% and 38.22% in O. officinalis and O. glaberrima, respectively. But in O. latifolia, signals were detected on the short arm and centromere area, with the percentage distances of 87.78±5.23 and 0, and the detection rate of 52.58%, respectively. The two BAC clones were syntenic and distributed in the same area of 4S chromosome of O. officinalis and O. glaberrima, and the homologous sequences of Bph15 were detected in DD genome of O. latifolia. Many signals on different chromosomes of O. glaberrima were observed without C0t-1 DNA blocking, showing that repetitive sequences were also homologous in three species. The comparative physical mapping analysis showed the location of Bph15 in these three species. The relationships among three species in term of the results of location of Bph15 were discussed, and the knowledge of the genetic relationship among different species in genus Oryza is helpful to conservation and utilization of Bph15. The evolutive mechanism of gene function in different genomes, diploid, and tetraploid species is also discussed.
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