DNA

Definition

Deoxyribonucleic acid; a double-stranded nucleic acid polymer that encodes the genetic information governing development, reproduction, and heritable traits in all cellular organisms. In arthropod biology, DNA serves as the primary substrate for molecular systematics, population genetics, and phylogenetic reconstruction. DNA barcoding—sequencing standardized gene regions such as the mitochondrial COI (cytochrome c oxidase subunit I) gene—has become a cornerstone of modern entomology, enabling rapid species identification, detection of cryptic diversity, and association of life stages (e.g., linking larvae to adult beetles) without rearing. Nuclear DNA markers (e.g., ribosomal 18S/28S, protein-coding loci) complement mitochondrial data for resolving deeper evolutionary relationships among arachnids and insects. DNA also underlies studies of adaptation (e.g., insecticide resistance mutations in mosquitoes), gene flow, and conservation genetics of threatened invertebrate populations.

Etymology

Initialism of deoxyribonucleic acid, coined in the 20th century as the molecular basis of heredity became established.

Example

Entomologists use DNA extracted from a single leg of a pinned museum specimen to sequence the COI barcode region, confirming that morphologically similar ant specimens from different elevations represent distinct cryptic species.

Synonyms

• Deoxyribonucleic acid

Related Terms

• RNA
• gene
• Genome
• Chromosome
• mitochondrial DNA
• COI
• DNA barcoding
• PCR
• sequencing
• molecular systematics
• Phylogenetics
• Genotype
• Nucleotide
• Base pair
• exon
• Intron

Usage Notes

DNA is treated as a mass noun in most biological contexts; the plural 'DNAs' appears primarily in technical contexts referring to multiple distinct DNA samples or molecules. Distinguish from RNA, which is typically single-stranded and functions in protein synthesis and gene expression. In entomological literature, 'DNA' alone often implies nuclear genomic DNA, whereas 'mtDNA' specifies the maternally inherited mitochondrial genome. The informal sense of DNA as 'fundamental nature' (e.g., 'in the DNA of the organization') is avoided in scientific writing.