Complementary DNA (cDNA)

Definition

Complementary DNA (cDNA) is a form of DNA synthesized from a messenger RNA (mRNA) template through the action of the enzyme reverse transcriptase. cDNA is often used in cloning and gene expression studies because it represents only the expressed genes of an organism.

5 Must Know Facts For Your Next Test

1. cDNA is created using reverse transcriptase, which synthesizes DNA from an mRNA template.
2. Unlike genomic DNA, cDNA contains no introns or non-coding regions.
3. cDNA libraries are essential tools for identifying and studying gene expression.
4. The process of creating cDNA involves isolating mRNA, reverse transcription to synthesize the first strand, and often a second-strand synthesis to complete the double-stranded cDNA.
5. cDNA is crucial in techniques like quantitative PCR (qPCR) and microarrays to measure mRNA levels.

Review Questions

• What enzyme is responsible for synthesizing cDNA from an mRNA template?
• How does cDNA differ from genomic DNA in terms of its composition?
• Why are cDNA libraries important in genetic research?

Related terms

Reverse Transcriptase: An enzyme that synthesizes complementary DNA from an RNA template.

mRNA: Messenger RNA; a type of RNA that conveys genetic information from DNA to the ribosome.

Genomic DNA: The complete set of DNA, including all of its genes and non-coding sequences, found within an organism's genome.