Deoxyribonucleic acid

Definition

A double-stranded nucleic acid polymer that encodes heritable genetic information through sequences of four nitrogenous bases—adenine, guanine, cytosine, and thymine—arranged along a deoxyribose-phosphate backbone. In arthropods, nuclear DNA is organized into chromosomes within the cell nucleus, while mitochondrial DNA (mtDNA) occurs as a circular molecule in mitochondria and is extensively used in molecular taxonomy due to its maternal inheritance and relatively rapid evolutionary rate.

Etymology

From deoxy- (indicating the absence of an oxygen atom at the 2' position of the ribose sugar), ribo- (referring to the pentose sugar), nucleic (from nucleus), and acid (denoting the phosphate group's acidic properties)

Example

DNA barcoding of the cytochrome c oxidase subunit I (COI) gene is routinely employed to distinguish cryptic species of parasitoid wasps that are morphologically identical but genetically divergent.

Synonyms

• DNA

Related Terms

• ribonucleic acid
• mitochondrial DNA
• Genome
• Chromosome
• Nucleotide
• polymerase chain reaction
• DNA barcoding
• Phylogenetics

Usage Notes

Abbreviated universally as DNA in scientific literature. Distinguish from RNA by sugar composition (deoxyribose versus ribose) and base content (thymine versus uracil). In entomological practice, 'DNA' without qualification usually implies nuclear genomic DNA, whereas mtDNA specifies the mitochondrial genome. The term is sometimes used loosely in field contexts to refer to extracted genetic material or sequence data rather than the molecule itself.