Sex matters in the birth of genes

摘要: Recent progress in technology has allowed an extraordinary refinement of our knowledge transcriptomes, revealing their unexpected complexity. In addition to the large number siRNAs and miRNAs, many noncoding RNA species are now known be transcribed by polymerase II (RNAPII), proximity or overlapping transcription units both sense antisense orientations, as well from DNA regions previously thought transcriptionally inert silent. This phenomenon, dubbed 'pervasive' transcription, appears evolutionary conserved all eukaryotes yeast human 1. These RNAs had escaped identification because very low abundance cells grown under standard physiological conditions where they eliminated degradative machineries shortly after RNAPII. Why even produce destined degradation is open question. However, it logic that use quality control mechanisms rapidly target potentially hazardous transcripts while preserving proper expression coding RNAs. Nevertheless, this not whole story, budding several examples beginning emerge involved gene regulation, particularly those arising ORFs. So far, regulation S. cerevisiae relies on itself act its generally leading inhibition through cis-acting transcriptional interference mechanisms, inducing repressive changes chromatin structure interesting analogy RNAi higher eukaryotes. What these instances RNA-mediated tell us pervasive just noise but genetic material can tested natural selection eventually evolve specific functions exploited for regulatory purposes.