Ribosomal protein genes rp 39(10 - 78), rp 39(11 - 40), rp 51, and rp 52 are not contiguous to other ribosomal protein genes in the Saccharomyces cerevisiae genome.

A library of recombinant phage containing EcoR1 fragments of Saccharomyces cerevisiae DNA has been constructed. This library was screened with four different recombinant plasmids, each containing a different yeast ribosomal protein gene, in order to isolate chromosomal fragments extending in both directions from these genes. These chromosomal fragments were assayed for the presence of additional ribosomal protein genes by hybridization selection and cell free translation, and none were found. These four regions are not closely linked to each other, since DNA from one domain does not cross hybridize with DNA from any of the other three, except for the sequences within the homologous ribosomal protein 39 gene pair. Northern blots demonstrate that although the concentrations of ribosomal protein mRNAs are diminished significantly in a strain containing the ts mutation rna2, transcripts from genes in these flanking segments are relatively unaffected.