Chromosome I as a possible site for some rRNA cistrons in <i>Saccharomyces cerevisiae</i>

Abstract

By hybridizing ribosomal RNA with DNA extracted from different disomic strains of ,mcct ',aromyces cerel,isiae, Goidberg et al. [ ! ] have shown that the 140 rRNA cistrons in yeast are non randomly distributed on the genome. None of their strains seemed to carry disomie chromosomes enriched for rRNA genes. tl0wevet, one mutant that showed a significantly lower hybridization plateau than a wild type haploid, turned out to have at least seven chromosomes in double portion. Resides indicating the presence of only a few, if an,.,, rRNA genes on these extra chromosomes, this illustrated some of the problems in identifying the aneupioids genetically. As also stated by Parry and Cox [2L it may be difficult to obtain stable yeast strains with disomy for one chromosome on~.y.