Abstract

MicroRNAs are short (~22nt) RNA regulatory molecules that repress protein translation. Because of their small size, genes encoding microRNAs frequently emerge from non-coding sequences during evolution. In this talk I will explore two evolutionary consequences of the high rate of novel microRNA emergence in the Drosophila genome. MicroRNAs tend to be clustered in the genome. I will show that this clustering is a consequence of a high rate of microRNA emergence within already transcribed regions. The role of tandem duplication in cluster formation may be negligible. I will also explore microRNAs with a sex-biased expression pattern. In the light of the available data, male biased microRNAs are the product of a high rate of novel microRNA emergence in the X chromosome. Novel gene emergence from non-coding sequences may have a bigger impact that duplication and selection in the evolution of microRNAs.

References

Marco A (2013) Sex-biased expression of microRNAs in Drosophila melanogaster. arXiv, 1312.3112.

Marco A, Ninova M, Ronsaugen M, Griffiths-Jones S (2013) Clusters of microRNAs emerge by new hairpins in existing transcripts. Nucleic Acids Res, 41:7745-7752