Silent but not static: accelerated base-pair substitution in silenced chromatin of budding yeasts.
Subtelomeric DNA in budding yeasts, like metazoan heterochromatin, is gene poor, repetitive, transiently silenced, and highly dynamic. The rapid evolution of subtelomeric regions is commonly thought to arise from transposon activity and increased recombination between repetitive elements. However, we found evidence of an additional factor in this diversification. We observed a surprising level of nucleotide divergence in transcriptionally silenced regions in inter-species comparisons of Saccharomyces yeasts. Likewise, intra-species analysis of polymorphisms also revealed increased SNP frequencies in both intergenic and synonymous coding positions of silenced DNA. This analysis suggested that silenced DNA in Saccharomyces cerevisiae and closely related species had increased single base-pair substitution that was likely due to the effects of the silencing machinery on DNA replication or repair.
Teytelman
Leonid
L
Department of Molecular & Cell Biology, University of California Berkeley, Berkeley, California, United States of America.
Eisen
Michael B
MB
Rine
Jasper
J
D001483:Base Sequence; D002843:Chromatin / Q000235:genetics*; D017124:Conserved Sequence; D004271:DNA, Fungal / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D020868:Gene Silencing; D008969:Molecular Sequence Data; D017354:Point Mutation; D020641:Polymorphism, Single Nucleotide; D012440:Saccharomyces / Q000235:genetics*; D016615:Telomere / Q000235:genetics; D014158:Transcription, Genetic
D002843:Chromatin; D004271:DNA, Fungal; D021901:DNA, Intergenic; D005656:Fungal Proteins