MBE Advance Access originally published online on April 15, 2008
Molecular Biology and Evolution 2008 25(7):1493-1502; doi:10.1093/molbev/msn094
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Research Articles |
Molecular Evolution of a Primate-Specific microRNA Family
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* State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
Kunming Primate Research Center, Chinese Academy of Sciences, Kunming, China
Graduate School of Chinese Academy Sciences, Beijing, China
E-mail: sub{at}mail.kiz.ac.cn
Accepted for publication April 10, 2008.
Lineage-specific microRNA (miRNA) families may contribute to developmental novelties during evolution. However, little is known about the origin and evolution of new miRNA families. We report evidence of an Alu-mediated rapid expansion of miRNA genes in a previously identified primate-specific miRNA family, drawn from sequencing and comparative analysis of 9 diverse primate species. Evolutionary analysis reveals similar divergence among miRNA copies whether they are within or between species, lineage-specific gain and loss of miRNAs, and gene pseudolization in multiple species. These observations support a birth-and-death process of miRNA genes in this family, implicating functional diversification during primate evolution. In addition, both secondary structure conservation and reduced single nucleotide polymorphisms density attest to functional constraint of this family in primates. Finally, we observed preferential expression of miRNAs in human placenta and fetal brain, suggesting a functional importance of this family for primate development.
Key Words: microRNA birth-and-death evolution Alu primates
Jianzhi Zhang, Associate Editor