Abstract

Over one third of the human genome appears to be regulated by miRNAs which are involved in fundamental cellular processes and are negative regulators of gene expression. MicroRNAs (miRNAs) are evolutionary conserved across broad phylogenetic distances and have gained considerable attention about evolution, genetic and phylogenetic analysis. Comparing sequences of miRNA precursors within a species and between closely related species should thus help to determine patterns of molecular evolution and the timescales at which different aspects of the evolution of miRNAs can be best investigated. In this study, miRNAs were analyzed for their relationship with each other and pattern of variations among different organisms, and it is hoped that it will enhance our understandings on the use of miRNAs in therapeutics for the treatment of various diseases which are the main focus of modern research these days in molecular studies. Four different sequences of human miRNAs (Homo sapiens miR-99-precursor-21, H. sapiensmicroRNA let-7a-1, H. sapiens microRNA 145 and H. sapiens microRNA 18a) were retrieved from the NCBI, and multiple sequence alignment and phylogenetic analysis of the miRNAs through UPGMA was performed which showed their relationship among each other and pattern of variations among different organisms.

Key words: MicroRNA (miRNA), phylogenetics, miR-99, microRNA let-7a-1, microRNA 145, microRNA 18a