Evolutionary dynamics of gene regulation by let-7 family of microRNAs in mammals

MicroRNA (miRNA) family members with paralogous sequences are generally believed to be generated by duplications, which play an important role in evolution process. But relatively little is known about the evolutionary principles of target recognition and repression of paralogous miRNA after duplication. To address this question, we investigated the evolution of gene regulation by let-7 family members in multiple mammalian species. We transfected let-7a and let-7b mimics into four mammalian kidney-derived cell lines respectively, and detected the alteration of transcriptomes by deep sequencing.Our results provide comprehensive and novel insights into the dynamics of gene regulation by let-7 family of miRNAs across species.