Incipient mitochondrial evolution in yeasts: II. The complete sequence of the gene coding for cytochrome b in Saccharomyces douglasii reveals the presence of both new and conserved introns and discloses major differences in the fixation of mutations in evolution☆

摘要: Abstract We have determined the complete sequence of mitochondrial gene coding for cytochrome b in Saccharomyces douglasii . The is 6310 base-pairs long and interrupted by four introns. first one (1311 base-pairs) belongs to group ID secondary structure, contains a fragment open reading frame with characteristic GIY … YIG motif, absent from cerevisiae inserted same site which introns 1 2 are Neurospora crassa Podospora anserina , respectively. next three S. homologous at positions display various degrees similarity ranging an almost identity (intron 4) moderate 3). compared structures intron RNAs, nucleotide amino acid sequences exons frames two species. rules that govern fixation mutations exon different: relative proportion occurring synonymous codons low some high exons. overall frequency much smaller than nuclear genes yeasts, contrary what has been found vertebrates, where more frequent. divergence modular: parts changed different mode tempo evolution.