cDNA or Complementary DNA

Complementary DNA or cDNA is a complimentary copy of a stretch of DNA produced by recombinant DNA technology.

It is the double-stranded DNA complement of an mRNA sequence which is synthesized in vitro from a mature RNA template using enzymes reverse transcriptase (to create a single strand of DNA from the RNA template) and DNA polymerase (to create the double-stranded DNA).

The reparation of cDNAs is often the first step in cloning DNA sequences of interest.

It is used as specific and sensitive probes in hybridization studies because cDNAs usually do not include regulatory or other controlling sequences, and so they can be used to identify (probe) and isolate genes and their associated sequences from genomic DNA.

cDNA clone

A double-stranded DNA molecule that is carried in a vector and was synthesized in vitro from an mRNA sequence by using reverse transcriptase and DNA polymerase.

cDNA cloning

A method of cloning the coding sequence of a gene, starting with its mRNA transcript. It is normally used to clone a DNA copy of a eukaryotic mRNA. The cDNA copy, being a copy of a mature messenger molecule, will not contain any intron sequences and may be readily expressed in any host organism if attached to a suitable promoter sequence within the cloning vector.

cDNA library

A collection of cDNA clones that were generated in vitro from the mRNA sequences isolated from an organism or a specific tissue or cell type or population of an organism.

Originally published at https://www.mbiology.com.