Question

What is complementary DNA (cDNA)?

Options

• A sequence of DNA as it is found in the genome

• Any sequence of cloned DNA

• DNA made from a mature mRNA template

• DNA made through the polymerase chain reaction

Answer 1

DNA made from a mature mRNA template

Explanation:

Complementary DNA (cDNA) is synthesized from a mature messenger RNA (mRNA) template using the enzyme reverse transcriptase. This process creates a DNA copy that corresponds only to the expressed genes (without introns) found in the mRNA, unlike genomic DNA which contains both introns and exons. cDNA is useful in cloning expressed genes and analyzing gene expression because it represents only the coding regions of a gene without intronic sequences.