rDNA在斑茅染色体的物理定位和染色体基数研究

Physical Mapping of rDNA on the Chromosomes of Erianthus Arundinaceus and Determination of Basic Chromosome Number

为了了解5S rDNA和45S rDNA在斑茅染色体上的分布情况及其染色体基数,利用荧光原位杂交技术在斑茅海南92-77(2n=60)和海南92-105(2n=60)的中期染色体和间期细胞核上进行5S rDNA和45S rDNA定位研究。结果表明在海南92-77和海南92-105的中期染色体和间期细胞核上45S rDNA位点均有6个信号位点,且均位于染色体短臂的端部上;这6个45S rDNA位点大小具有明显的差异,说明斑茅的45S rDNA的拷贝数存在差异。5S rDNA位点在海南92-77和海南92-105均有6个信号位点,且均位于染色体长臂的着丝粒附近;5S rDNA位点大小相差无几,说明斑茅的5S rDNA的拷贝数差异不大。因此,可以推断染色体数目为60的斑茅染色体基数为x=10。

In order to know the physical mapping of 5S rDNA and 45S rDNA on the chromosomes of E.arundinaceus and determination of basic chromosome number,the E.arundinaceus chromosome localization of 5S rDNA and 45S rDNA was studied by fluorescence in situ hybridization on metaphase chromosomes in Hainan 92-77(2n=60)and Hainan 92-105(2n=60).The results showed that the number of 45S rDNA site signal loci were six at somatic chromosomes of metaphase and cell nucleus of interphase in both Hainan 92-77 and Hainan 92-105,and the signal loci of 45S rDNA was located in the short arm end of six chromosomes.Among them,loci were different,suggesting that the copy number of 45S rDNA was different.The number of 5S rDNA site signal loci were six in both Hainan 92-77 and Hainan 92-105,and the signal loci of 45S rDNA was located near the long arm of chromosome centromere,all the 6 loci were of similar size,suggesting that the copy number of 5S rDNA was similar.Therefore,the basic chromosome number of E.arundinaceus with 2n=60 was determined as x=10.