LIFE WITH 6000 GENES

The genome of the yeast Saccharomyces cerevisiae has been completely s equenced through a worldwide collaboration. The sequence of 12,068 kil obases defines 5885 potential protein-encoding genes, approximately 14 0 genes specifying ribosomal RNA, 40 genes for small nuclear RNA molec ules, and 275 transfer RNA genes. In addition, the complete sequence p rovides information about the higher order organization of yeast's 16 chromosomes and allows some insight into their evolutionary history. T he genome shows a considerable amount of apparent genetic redundancy, and one of the major problems to be tackled during the next stage of t he yeast genome project is to elucidate the biological functions of al l of these genes.