What is cDNA?
cDNA or complementary DNA is a type of DNA that is sourced from mRNA or messenger RNAs. Through a process involving the catalytic effects of DNA polymerase and reverse transcriptase, cDNA is formed and synthesized. “Complementary” is the name used for this DNA because the molecular sequence on one strand is chemically similar to the other strand. cDNA is said to be formed and synthesized in order to clone the genes of cells with nuclear membranes for those that don’t have it (prokaryotes). Besides cDNA synthesis through catalytic enzymes, cDNA may also be produced through the use of retroviruses like SIV, HIV1 and HIV2. These particular viruses will be introduced into the host cells to create a substance called a provirus. This provirus will be in-charge of replicating the genes of its host. The process is not a direct replication of genes though. When proviruses are used, the replicated genes will be forwarded to the offspring of the original cell.
cDNAs are formed and synthesized from mRNA because they are easier handled when it comes to coding sequences. RNAs can also be degraded faster by various enzymes and so sequencing will be much more difficult to do. So with the mRNA isolated, one just needs to secure reagents and components to start cDNA synthesis. By action of the DNA polymerase, the initial strand will be formed. After which, the mRNA is taken out from the mix to allow for the synthesis of the second and final strand. Both strands will then become the complementary DNA and both will also have the same coding sequence.
Because DNAs can be replicated through the use of cDNA synthesis, these DNA types are extensively used for researches and experiments. Because of this technology, some people have voiced their disapproval of this technique in modifying the normal genetic composition of food items through tampering with the DNA structure.