Kaback D B, Halvorson H O
Proc Natl Acad Sci U S A. 1977 Mar;74(3):1177-80. doi: 10.1073/pnas.74.3.1177.
When a strain of Saccharomyces cerevisiae monosomic for chromosome I and initially deficient for 25% of the genes coding for ribosomal RNA is repeatedly subcultured, the number of these genes increases to and remains stable at the number in the wild type. This strain shows 2:2; viable: inviable first division segregation and hemizygosity for the ade1 gene (a chromosome I marker), evidence that the strain is still monosomic for chromosome I. The increase in the number of genes coding for ribosomal RNA in yeast may be analogous to the magnification of the ribosomal RNA genes in Drosophila melanogaster bobbed mutants.
当一株一号染色体单体的酿酒酵母菌株最初缺失25%的核糖体RNA编码基因，经反复传代培养后，这些基因的数量会增加至野生型的数量并保持稳定。该菌株表现出2:2的比例；有活力：无活力的第一次分裂分离以及ade1基因（一号染色体标记）的半合子状态，这证明该菌株一号染色体仍为单体。酵母中核糖体RNA编码基因数量的增加可能类似于黑腹果蝇截毛突变体中核糖体RNA基因的扩增。
