title: Evolution of the let-7 microRNA family.
abstract: The increase of bodyplan complexity in early bilaterian evolution is correlates with the advent and diversification of microRNAs. These small RNAs guide animal development by regulating temporal transitions in gene expression involved in cell fate choices and transitions between pluripotency and differentiation. One of the two known microRNAs whose origins date back before the bilaterian ancestor is mir-100. In Bilateria, it appears stably associated in polycistronic transcripts with let-7 and mir-125, two key regulators of development. In vertebrates, these three microRNA families have expanded to form a complex system of developmental regulators. In this contribution, we disentangle the evolutionary history of the let-7 locus, which was restructured independently in nematodes, platyhelminths, and deuterostomes. The foundation of a second let-7 locus in the common ancestor of vertebrates and urochordates predates the vertebrate-specific genome duplications, which then caused a rapid expansion of the let-7 family.
authors.affiliation: Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Hertel
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bartschat
authors.forename: Axel
authors.initials: A
authors.lastname: Wintsche
authors.forename: Christian
authors.initials: C
authors.lastname: Otto
authors.forename: Peter F
authors.initials: PF
authors.lastname: Stadler
mesh_terms: D000818:Animals; D001483:Base Sequence; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D019143:Evolution, Molecular; D006039:Gnathostoma / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D035683:MicroRNAs