title: In silico genetic robustness analysis of microRNA secondary structures: potential evidence of congruent evolution in microRNA.
abstract: BACKGROUND
  Robustness is a fundamental property of biological systems and is defined as the ability to maintain stable functioning in the face of various perturbations. Understanding how robustness has evolved has become one of the most attractive areas of research for evolutionary biologists, as it is still unclear whether genetic robustness evolved as a direct consequence of natural selection, as an intrinsic property of adaptations, or as congruent correlate of environment robustness. Recent studies have demonstrated that the stem-loop structures of microRNA (miRNA) are tolerant to some structural changes and show thermodynamic stability. We therefore hypothesize that genetic robustness may evolve as a correlated side effect of the evolution for environmental robustness.
  
  
  RESULTS
  We examine the robustness of 1,082 miRNA genes covering six species. Our data suggest the stem-loop structures of miRNA precursors exhibit a significantly higher level of genetic robustness, which goes beyond the intrinsic robustness of the stem-loop structure and is not a byproduct of the base composition bias. Furthermore, we demonstrate that the phenotype of miRNA buffers against genetic perturbations, and at the same time is also insensitive to environmental perturbations.
  
  
  CONCLUSIONS
  The results suggest that the increased robustness of miRNA stem-loops may result from congruent evolution for environment robustness. Potential applications of our findings are also discussed.
authors.affiliation: Beijing Institute of Radiation Medicine, Beijing 100850, China. shuwj@bmi.ac.cn
authors.forename: Wenjie
authors.initials: W
authors.lastname: Shu
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Bo
authors.forename: Ming
authors.initials: M
authors.lastname: Ni
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zheng
authors.forename: Shengqi
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D008957:Models, Genetic; D015233:Models, Statistical; D009154:Mutation; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D017423:Sequence Analysis, RNA
chemical_list: D035683:MicroRNAs