Micro-RNAs is a diminutive class of noncoding RNA molecules having an approximated length of about 18-24 nucleotides. The major function of the micro-RNAs (miRNAs) is the regulation of the cellular processes. According to the recent research it is depicted that miRNA is the most appropriate and precise representation of cell type and condition than the messenger RNA transcriptome. MiRNAs are sequentially numbered hence being registered officially in miRBASE, which absolutely contain sequence data for herald and mature molecules as well as further information.
After a wide range of research through microarray analysis of forensic blood and saliva that was carried out concerning micro-RNA it was confirmed that micro-RNAs are forensically relevant molecular species. MiRNAs have the ability to down regulate gene expression through base- pairing with the three regions of target messenger RNAs that have not yet been translated.
After a diverse study and examination of the miRNAs, the research centers have been able to successfully identify more than 700 types of miRNAs that the homo-sapiens do posses. It has also been acknowledged through bioinformatics that the human genome do posses at least 800 miRNAs which is approximately 3% of the total number of all protein coding genes that presently exist. The typical examples of blood miRNAs include miR-126, miR-150, and miR-451 while the saliva miRNAs include miR-200c, miR-203, and miR-205.
It has also been observed that 70% of all the mammalian messenger RNAs are subjected to selective pressure in order to maintain the sequence integrity of their micro-RNA binding sites as compared to those of miRNAs making it impossible for most of the biological processes to occur without being altered.
Micro-RNA has proofed to poses a variety of advantages as compared to the messenger RNA. Due to its diminutive size of about 22nt, it enables the mature miRNA to be more stable as compared to the mRNA which is susceptible to deterioration by chemical or physical actions. Which is of paramount importance in forensic settings as it renders mature miRNAs notably less susceptible against fractionation by chemical and physical environmental strain?
Another merit of the micro-RNA as compared to the messenger RNA is that miRNA profiling, performed better in classifying even weakly differentiated tumors than did mRNA profiling with several thousand mRNAs, implying that the miRNome is a more precise and meaningful representation of a cell type and condition than the mRNA transcriptome.
It has also been discovered that due to the ability of the micro-RNAs to be regulated, it is possible to represent a new instance of regulatory control over gene expression programs in many organisms. MiRNAs are capable of classifying the minute and less active differentiated tumors as compared to the messenger RNAs.