Rapid evolution of noncoding RNAs: lack of conservation does not mean lack of function.
The mammalian transcriptome contains many non-protein-coding RNAs (ncRNAs), but most of these are of unclear significance and lack strong sequence conservation, prompting suggestions that they might be non-functional. However, certain long functional ncRNAs such as Air and Xist are also poorly conserved. In this article, we systematically analyzed the conservation of several groups of functional ncRNAs, including miRNAs, snoRNAs and longer ncRNAs whose function has been either documented or confidently predicted. As expected, miRNAs and snoRNAs were highly conserved. By contrast, the longer functional non-micro, non-sno ncRNAs were much less conserved with many displaying rapid sequence evolution. Our findings suggest that longer ncRNAs are under the influence of different evolutionary constraints and that the lack of conservation displayed by the thousands of candidate ncRNAs does not necessarily signify an absence of function.
Pang
Ken C
KC
ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland, Brisbane QLD 4072, Australia.
Frith
Martin C
MC
Mattick
John S
JS
D000818:Animals; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics; D020537:RNA, Small Nucleolar / Q000235:genetics; D022661:RNA, Untranslated / Q000235:genetics*
D035683:MicroRNAs; D020537:RNA, Small Nucleolar; D022661:RNA, Untranslated