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采用栽培稻遗传图第 4连锁群中与抗稻瘿蚊基因 ,Gm- 6和 Gm- 2等位的 RFL P标记 RG2 14和 RZ5 6 9筛选出来的两个 BAC克隆为探针 ,对药用野生稻进行了荧光原位杂交物理定位。两个 BAC克隆的大小分别为 5 0 kb和86 kb,在 Cot- 1DNA封阻的情况下它们均被定位于药用野生稻第 4染色体长臂 ,与着丝粒百分距为 72 .33± 4.40、77.10± 2 .40 ,信号检出率分别为 6 1.2 %和 5 9.5 %。与此同时 ,用 RG2 14和 RZ5 6 9对药用野生稻进行了杂交 ,它们也被定位于药用野生稻第 4染色体长臂 ,与着丝粒百分距分别为 74.18± 2 .6 2和 78.2 3± 2 .31,信号检出率分别为 8.3%和 9.4%。 BAC克隆的 RFL P标记探针杂交位置几乎一致 ,这表明在栽培稻和野生稻中 RFL P标记 RG2 14和RZ5 6 9都在同一 BAC克隆的大插入片段中 ,药用野生稻与抗性基因 Gm- 6和 Gm- 2同源顺序就在第 4染色体信号出现的相应位置。药用野生稻第 4染色体的确定是根据 Jena等 (1994)和本研究的 RFL P的杂交结果进行的。文中讨论了利用栽培稻 BAC克隆对药用野生稻进行原位杂交物理作图的可行性等问题。
Two BAC clones selected from the RFL P markers RG2 14 and RZ5 6 9 in the fourth linkage group of the genetic map of cultivated rice with resistance to Gallid mosquito, Gm-6 and Gm-2 were used as probes. Wild rice was subjected to fluorescence in situ hybridization physical mapping. The size of the two BAC clones was 50 kb and 86 kb, respectively. When the Cot-1 DNA was blocked, they were all located on the long arm of the fourth chromosome of O. officinalis with a centromeric percentage of 72.33 ± 4.40,77.10 ± 2.40, the signal detection rates were 6 1.2% and 5 9.5% respectively. In the meantime, the wild type hybrid rice was crossed with RG2 14 and RZ5 6 9, and they were also located on the long arm of the fourth chromosome of O. officinalis with centromere percentages of 74.18 ± 2 .62 And 78.2 3 ± 2.31, the signal detection rate was 8.3% and 9.4% respectively. The RFL P-labeled probes hybridized almost identically to the BAC clones, indicating that the RFL P markers RG2 14 and RZ5 6 9 were both in the large insert of the same BAC clone in both cultivated and wild rice, The homologous sequence of Gm-6 and Gm-2 is at the corresponding position where signal of Chromosome 4 appears. The determination of the fourth chromosome of O. officinalis was based on the hybridization results of Jena et al. (1994) and the RFL P in this study. In this paper, the feasibility of using in situ hybridization mapping of medicinal wild rice with BAC clones in cultivated rice was discussed.