DNA probe

Definition

A single-stranded nucleic acid fragment, typically 15–10,000 nucleotides in length, that is labeled with a radioactive, fluorescent, or chemiluminescent tag and used to detect complementary target sequences through molecular hybridization. In arthropod research, DNA probes enable specific detection of species-diagnostic loci, sex-linked markers, or pathogen nucleic acids within vector tissues without prior sequencing.

Etymology

From the initialism DNA (deoxyribonucleic acid) + probe, reflecting its function as a sequence-specific detection tool.

Example

A fluorescently labeled DNA probe targeting the ribosomal ITS2 region distinguishes cryptic Anopheles mosquito species that are morphologically identical but differ in vector competence for malaria parasites.

Synonyms

• hybridization probe
• gene probe
• nucleic acid probe

Related Terms

• PCR
• qPCR
• in situ hybridization
• FISH
• Species complex
• molecular taxonomy
• vector surveillance

Usage Notes

Distinguished from PCR primers by function: probes hybridize to internal target sequences for detection, whereas primers initiate enzymatic amplification at termini. In entomological diagnostics, probes are often deployed in real-time qPCR assays or FISH (fluorescence in situ hybridization) to localize Wolbachia, trypanosomes, or viral pathogens within insect tissues. The term 'probe' alone is ambiguous; 'DNA probe' specifies the nucleic acid chemistry. RNA probes (riboprobes) share similar applications but require RNase-free handling.