Deoxyribonukleinsyre

Deoxyribonukleinsyre, commonly known as DNA, is the molecule that stores the genetic instructions essential for development, functioning, growth, and reproduction in almost all organisms. It is a long polymer built from nucleotides, each containing a sugar (deoxyribose), a phosphate group, and a nitrogenous base. The bases are adenine, thymine, cytosine, and guanine. DNA typically forms a double helix of two antiparallel strands held together by hydrogen bonds between complementary bases: A with T and C with G. The sequence of bases encodes genetic information.

DNA is located mainly in the cell nucleus (nuclear DNA), with small amounts in mitochondria; in plants, chloroplasts also contain DNA. The genome comprises genes and noncoding regions. Gene expression proceeds through replication, transcription, and translation: replication copies DNA for cell division; transcription produces RNA templates; translation uses RNA to synthesize proteins.

Historically, the discovery of the DNA double helix in 1953 by Watson and Crick, building on work by Rosalind Franklin and Maurice Wilkins, established the basis for modern molecular biology.

Functionally, DNA stores hereditary information and guides cellular processes. Variation arises by mutations and recombination, fueling evolution. In medicine, forensics, and biotechnology, DNA analysis, sequencing, and genome editing are central tools.