45S rDNA基因在新麦草染色体上的分布

The Distribution of 45S rDNA in Chromosome of Russian Wild Ryegrass

分析rDNA基因位点在染色体上的分布可以对新麦草染色体进行识别和分析其基因组特征。利用FISH和顺序C-分带-FISH技术将45S rDNA定位于新麦草细胞分裂中期染色体上,结果表明,45S rDNA在二倍体新麦草染色体上有6个主要分布位点,另外几条染色体在两臂中部或长臂末端还显示出较弱的杂交信号,信号强度显示蒙农4号新麦草基因组具有一定杂合性。分析确定新麦草的45S rDNA基因主位点分别位于N1染色体短臂末端、N3染色体短臂末端以及N5染色体短臂末端,推测这3对染色体是NOR染色体。

Chromosome and genome of Russian wild rye could be analyzed by the rDNA gene location.Chromo-some was analyzed by sequential C-banding and 45S rDNA FISH.There were 6 main 45S rDNA sites located in the end of short arms of 3 pairs of diploid chromosome.They were chromosome N1,N3 and N5,which can be speculated as NOR chromosome.There were also weak hybridization signal on some long arm of chromosome.Heterozygosity could be identified in Genome of variety Mengnong No.4 by hybridization signal strength.