THE NUCLEOTIDE-SEQUENCE OF SACCHAROMYCES-CEREVISIAE CHROMOSOME-XIII

Systematic sequencing of the genome of Saccharomyces cerevisiae has re vealed thousands of new predicted genes and allowed analysis of long-r ange features of chromosomal organization. Generally, genes and predic ted genes seem to be distributed evenly throughout the genome, having no overall preference for DNA strand. Apart from the smaller chromosom es, which can have substantially lower gene density in their telomeric : regions(1-3), there is a consistent average of one open reading fram e (ORF) approximately every two kilobases. However, one of the most su rprising findings for a eukaryote with approximately 6,000 genes was t he amount of apparent redundancy in its genome. This redundancy occurs both between individual ORFs and over more extensive chromosome regio ns, which have been duplicated preserving gene order and orientation(4 -6). Here we report the entire nucleotide sequence of chromosome XIII, the sixth-largest S. cerevisiae chromosome, and demonstrate that its features and organization are consistent with those observed for other S. cerevisiae chromosomes. Analysis revealed 459 ORFs, 284 have not b een identified previously. Both intra- and interchromosomal duplicatio ns of regions of this chromosome have occurred.