THE NUCLEOTIDE-SEQUENCE OF SACCHAROMYCES-CEREVISIAE CHROMOSOME-XIV AND ITS EVOLUTIONARY IMPLICATIONS

In 1992 we started assembling an ordered library of cosmid clones from chromosome XIV of the yeast Saccharomyces cerevisiae. At that time, o nly 49 genes were known to be located on this chromosome(1) and we est imated that 80% to 90% of its genes were yet to be discovered. In 1993 , a team of 20 European laboratories began the systematic sequence ana lysis of chromosome XIV. The completed and intensively checked final s equence of 784,328 base pairs was released in April, 1996 (ref. 2), Su bstantial parts had been published before(3-22) or had previously been made available on request. The sequence contained 419 known or presum ptive protein-coding genes, including two pseudogenes and three retrot ransposons, 14 tRNA genes, and three small nuclear RNA genes. For 116 (30%) protein-coding sequences, one or more structural homologues were identified elsewhere in the yeast genome. Half of them belong to dupl icated groups of 6-14 loosely linked genes, in most cases with conserv ed gene order and orientation (relaxed interchromosomal synteny). We h ave considered the possible evolutionary origins of this unexpected fe ature of yeast genome organization.