Microevolution of nematode miRNAs reveals diverse modes of selection.
Bottom Line: We also show that new miRNAs evolve faster than older miRNAs but that selection nevertheless favors their persistence.Moreover, we demonstrate substantial nucleotide divergence of pre-miRNA hairpin alleles between populations and sister species.These findings from the first global survey of miRNA microevolution in Caenorhabditis support the idea that changes in gene expression, mediated through divergence in miRNA regulation, can contribute to phenotypic novelty and adaptation to specific environments in the present day as well as the distant past.
Affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada email@example.com.Show MeSH
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Mentions: We next sought to address the relationship between phylogenetic conservation and sequence polymorphism. When we classify C. remanei miRNAs based on the degree of preservation of their family in other Caenorhabditis species (unique vs. conserved), we find that evolutionary signatures both in the short term (polymorphism) and longer term (divergence) are concordant with faster evolution of those miRNAs unique to C. remanei and C. latens (supplementary fig. S6, Supplementary Material online). However, we detect qualitatively similar signatures of purifying selection both for unique and conserved miRNAs (fig. 5). Altogether, these findings are consistent with more rapid sequence evolution for newly emerging miRNAs, as observed in Drosophila (Nozawa et al. 2010; Mohammed et al. 2013; Lyu et al. 2014), nevertheless coupled to selection favoring their persistence.Fig. 5.—
Affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Canada firstname.lastname@example.org.