Petes T D, Botstein D
Proc Natl Acad Sci U S A. 1977 Nov;74(11):5091-5. doi: 10.1073/pnas.74.11.5091.
A diploid strain of yeast (Saccharomyces cerevisiae) was found to be heterozygous for two forms of the highly repetitious ribosomal DNA. These forms could be distinguished by the pattern of fragments produced after digestion with the site-specific restriction endonuclease EcoRI. The mode of inheritance of ribosomal DNA was determined by tetrad analysis. Of 14 tetrads analyzed, 12 clearly showed the ribosomal DNA forms segregating as a single Mendelian unit. The simplest interpretation of this result is that all of the approximately 100 copies of the ribosomal DNA genes of the yeast cell are located on one chromosome and that meiotic recombination within these genes is suppressed. Two of the 14 tetrads showed the segregation patterns expected as the result of mitotic recombination within the ribosomal DNA.
发现一株二倍体酵母（酿酒酵母）对于两种高度重复的核糖体DNA是杂合的。这些形式可以通过用位点特异性限制性内切酶EcoRI消化后产生的片段模式来区分。核糖体DNA的遗传模式通过四分体分析来确定。在分析的14个四分体中，12个清楚地显示核糖体DNA形式作为一个单一孟德尔单位分离。对这一结果最简单的解释是，酵母细胞中大约100个核糖体DNA基因拷贝全部位于一条染色体上，并且这些基因内的减数分裂重组受到抑制。14个四分体中的两个显示出预期的分离模式，这是核糖体DNA内有丝分裂重组的结果。
