Plasticity vs Mutation. The role of microRNAs in human adaptation.

The variability potential of a phenotype, on the background of the same genotype, is termed "phenotypic plasticity". This is considered by some scientists as a more important evolutionary procedure than mutation based natural selection. In this review, I discuss the fact that microRNAs have the potential to determine significantly the spectrum of phenotypic plasticity by regulating translation rate. MicroRNAs constitute a complicate network that can adjust at a variety of external environmental stimuli. They can also rebalance genome's function after genomic duplication events. Despite this, phenotypic plasticity is not limitless. Modern way of human life is pushing our physiology at its limits. On the other site, old people have dysregulated microRNA levels, this reducing their potential for plastic phenotypes. Can we intervene correcting this dysregulation? The system is very complicate and our knowledge is incomplete. More research is needed in order to understand deeper the exact relation of microRNAs with plasticity and aging, by taking advantage on the newly developed high-throughput methods.