The DNA sequence of cosmid 14-13b from chromosome XIV of S. cerevisiae reveals an unusually high number of overlapping ORFs.

This work is part of the effort for sequencing chromosome XIV of Saccharomyces cerevisiae. Cosmid 14-13b contains a 37.8 kb insert derived from a partial Sau3A digestion of the genome, cloned into the BamHI site of the vector Pou6. The strategy used for sequencing is based on the fragmentation of the whole cosmid by sonication, followed by shotgun sequencing on an Applied Biosystem DNA sequencer. The clones with inserts corresponding to the vector were identified by dot-blot hybridization, without the need of sequencing. The analysis of the DNA sequence reveals 29 open reading frames (ORFs) longer than 300 bases. Nine ORFs are internal to some other ORFs. Similarity searches against DNA and protein data banks show that six ORFs correspond to already known yeast genes (OMP1, PSU1, MLS1, RPC19, DBP2, CYB5) and one ORF matches the sequence of a putative yeast gene (ESBP6)