DNA vs cDNA
DNA and cDNA are kinds of nucleic acids; both are made up of nucleotides. Even though, they are structurally similar, their function and the way of synthesis differs from each other.
DNA is a nucleic acid that contains the genetic instructions used in all eukaryotes and some prokaryotes. It is the main constituent of the chromosomes and carries the genetic information in the cell from parents to offspring. The DNA molecule consists of two long polynucleotide chains, which are twisted into a double helix. The backbones of these two chains are made up of sugars and phosphate groups joined by hydrogen bonds between the complementary bases adenine and thymine or cytosine and guanine. An important property of DNA is that, it is self-replicating, which means it can replicate or make copies of itself. It plays a major role in protein synthesis.
cDNA stands for Complementary DNA. This is a form of DNA artificially synthesized by a given mature messenger RNA (mRNA), which serves as a template in the presence of reverse transcriptase enzyme. In most eukaryotes, expressed segments of the gene are called exons; exons are separated by introns (intervening sequences), which are not coding sequences. Generaly, genomic DNA is transcribed in to a mRNA by a process called transcription that is excising these introns by splicing. Prokaryotic cells do not contain introns, hence, unable to remove introns from eukaryotic DNA and make functional mRNA. Therefore, eukaryotic DNA can not be cloned directly in to prokaryotic cells to make specific eukaryotic proteins. In the production of gene clones, mature eukaryotic mRNA is obtained from the cell. The enzyme reverse transcriptase is used to convert the purified eukaryotic mRNA in to double stranded complementary DNA(cDNA) that can then be cloned in to a bacterial cell.
DNA vs cDNA
DNA is synthesized naturally while cDNA is a form of DNA which is synthesized by the scientist for their experimental purpose. Genomic DNA contains both introns and exons but cDNA is made up of only exons, which codes for specific functions. cDNAs are much shorter, as introns can span thousands of base pairs.