ABSTRACT
Molecular biology has become a crucial tool for identifying new genes with importance in medicine, agriculture, environment, and health. One of the essential molecular techniques with multiple advancements and applications is polymerase chain reaction (PCR). This technique was originally developed by Kary Mullis in 1983 and since then it has become an essential tool for the amplification of nucleic acids. PCR is a fairly simple technique used to detect and amplify a nucleic acid sequence. In the recent years, modifications have been introduced in this technique to develop different variants of the basic PCR method. Another advanced technique developed recently is RNA interference. RNA interference is a gene regulatory mechanism that downregulates the expression of genes by either suppressing the transcription or by activating a sequence-specific mRNA degradation. The natural functions of RNAi are to regulate the developmental programs of eukaryotic organisms and protection of genome against viruses and transposons. In eukaryotic organisms, two major categories of small RNAs including short interfering RNAs (siRNAs) and microRNAs (miRNAs) regulate endogenous gene expression and defend the genome from invasive nucleic acids. RNAi provides a rapid means of silencing a specific gene by introducing double-stranded DNA sequence into the cell. Pioneering work on RNAi was reported in plants, and later on such mechanism was also described in nematodes, insects, and human cells.
