Cramer J H, Farrelly F W, Rownd R H
Mol Gen Genet. 1976 Nov 17;148(3):233-41. doi: 10.1007/BF00332897.
The size and degree of homogeneity of the repetitive units in purified ribosomal DNA (gamma DNA) from Saccharomyces cerevisiae have been analyzed by restriction endonuclease digestion and heteroduplex mapping. Digestion of the gamma DNA with EcoRI yields seven fragments, digestion with Hind II+III yields five fragments, digestion with Hind III alone yields two fragments, and digestion with Sma I yields one fragment. The sum of the fragment molecular weights after digestion with each of the endonucleases is 5.5-5.6 x 10(6). When the DNA strands of the Sma I fragment are dissociated and reannealed, only homoduplexes are formed. We have concluded from these results that the repeating units in yeast ribosomal DNA are 5.6 x 10(6) datons and are homogeneous in size and composition.
通过限制性内切酶消化和异源双链图谱分析，对来自酿酒酵母的纯化核糖体DNA（γDNA）中重复单元的大小和同源程度进行了研究。用EcoRI消化γDNA产生7个片段，用Hind II + III消化产生5个片段，仅用Hind III消化产生2个片段，用Sma I消化产生1个片段。用每种内切酶消化后片段分子量之和为5.5 - 5.6×10⁶。当Sma I片段的DNA链解离并重新退火时，仅形成同源双链体。从这些结果我们得出结论，酵母核糖体DNA中的重复单元为5.6×10⁶道尔顿，且大小和组成均一。
