Genomic Exploration of the Hemiascomycetous Yeasts: 19. Ascomycetes-specific genes

Comparisons of the 6213 predicted Saccharomyces cervisiae open reading fram e (ORF) products with sequences from organisms of other biological phyla di fferentiate genes commonly conserved in evolution from 'maverick' genes whi ch have no homologue in phyla other than the Ascomycetes, We show that a ma jority of the 'maverick' genes have homologues among other yeast species an d thus define a set of 1892 genes that, from sequence comparisons, appear ' Ascomycetes-specific'. We estimate, retrospectively, that the S. cervisiae genome contains 5651 actual protein-coding genes, 50 of which were identifi ed for the first time in this work, and that the present public databases c ontain 612 predicted ORFs that are not real genes. Interestingly, the seque nces of the 'Ascomycetes-specific' genes tend to diverge more rapidly in ev olution than that of other genes. Half of the 'Ascomycetes-specific' genes are functionally characterized in S. cerevisiae, and a few functional categ ories are over-represented in them, (C) 2000 Federation of European Biochem ical Societies. Published by Elsevier Science B.V. All rights reserved.