Which type of DNA is often used for cloning and recombinant DNA technology?

The best choice for DNA often used in cloning and recombinant DNA technology is cDNA, or complementary DNA. cDNA is synthesized from messenger RNA (mRNA) through a process called reverse transcription. This transformation is particularly useful because cDNA represents only the protein-coding sequences of genes, excluding non-coding regions, which makes it more practical for cloning purposes.

When researchers want to produce specific proteins or study gene expression, they can create cDNA libraries that reflect the genes active in particular tissues or conditions. These clones can then be inserted into plasmids or other vectors for further manipulation, such as producing proteins or studying gene function.

Genomic DNA contains the entire genetic content of an organism, including both coding and non-coding regions, which makes it less efficient for experiments focused specifically on expressing proteins. RNA and mRNA are involved in protein synthesis but are not used directly for cloning due to their instability and the necessity for conversion into stable DNA forms for manipulation.

Thus, cDNA is especially advantageous in cloning and recombinant DNA technology due to its focus on expressed genes and its compatibility with various cloning techniques.