Isolation of Nucleic Acids

Nucleic acid isolation is the process of extracting DNA or RNA from cells in a relatively pure form that can be used for downstream investigations, such as gene amplification and sequencing. Purified RNA must be converted to complementary DNA (cDNA) before using it for PCR. The reason for the conversion is that PCR works on the principle of a double-stranded macromolecule. Therefore, based on the downstream method and study objectives, nucleic acids can be isolated from either whole cellular or subcellular fractions (e.g., nucleus, cytoplasm, or membrane-bound organelles). This chapter will discuss the general principles of DNA/RNA isolation from the whole cell, nucleus, and cytoplasm. Additionally, converting RNA to cDNA is also covered as it is an essential prerequisite step for detecting RNA viruses using PCR.