采用荧光原位杂交技术对45S rDNA在栽培高粱×拟高粱、甜高粱×拟高粱F1的有丝分裂和减数分裂染色体进行定位研究。在有丝分裂中期染色体上2个杂种分别检测到2个杂交信号, 在减数分裂粗线期、终变期、中期Ⅰ染色体上45S rDNA位于一个二价体上, 说明这两个杂种携带45S rDNA的染色体为同源染色体。根据45S rDNA位点随细胞减数分裂过程的位置变化, 表明这两个杂种染色体配对行为正常, 平均构型为2n=2x=20(10Ⅱ), 证明45S rDNA可作为染色体的一个识别指标间接地观察细胞减数分裂过程染色体的变化行为。
By means of fluorescence in situ hybridization (FISH), we located and analyzed the sites of the 45S rDNA on the F1 hybrids of S. bicolor × S. propinquum and S. dochna×S.propinquum. Two signals of 45S rDNA were mapped on the mitotic metaphase chromosomes in the F1 hybrids, respectively, and one signal was present on a bivalent during meiotic of synaptene, diakinesis, and metaphase I. We inferred that the two mitotic chromosomes carrying 45S rDNA were homolo-gous pairs. Considering the signals of 45S rDNA location during meiotic process, chromosome pairing of these two F1 hy-brids was normal with an average pairing configuration of 2n=2x=20 (10 II). Our results indicated that 45S rDNA could provide a landmark for identification of individual chromosome during meiosis indirectly.
