Simple Mendelian Inheritance of the Repeating Yeast Ribosomal DNA Genes

The yeast Saccharomyces cerevisiae has approximately 100–140 copies per haploid genome of the genes which code for ribosomal RNA (rRNA) (Schweizer et al. 1969). Each ribosomal gene codes for four species of ribosomal RNA: the 25S, 18S, 5.8S, and 5S rRNA (Udem and Warner 1972; Maxam et al. 1977; T. Petes et al., in prep.). In this paper we examine the inheritance of these repeating sequences.