Origins and Evolution of MicroRNA Genes in Drosophila Species

摘要: MicroRNAs (miRs) regulate gene expression at the posttranscriptional level. To obtain some insights into origins and evolutionary patterns of miR genes, we have identified genes in genomes 12 Drosophila species by bioinformatics approaches examined their changes. The results showed that extant ancestral had more than 100 frequent gains losses occurred during evolution. Although many appear to originated from random hairpin structures intronic or intergenic regions, duplication has also contributed generation new genes. Estimating rate nucleotide substitution found newly arisen a similar synonymous sites protein-coding evolve almost neutrally. This suggests most not acquired any important function would become inactive. By contrast, old show much lower rate. Moreover, paired unpaired tend remain unchanged Therefore, once functions, they evolved very slowly, maintaining essentially same for long time.