nukleiini

Nukleiini refers to nucleic acids, the biopolymers that store and transmit genetic information in living organisms. The two primary types are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA is the main repository of genetic information in most organisms, while RNA plays diverse roles in gene expression and regulation.

Historically, the substance was first identified by Friedrich Miescher in 1869 as “nuclein,” later understood as a nucleic acid. The work of Albrecht Kossel and others established the chemical nature of nucleic acids and their components. In the mid-20th century, the genetic role of DNA was demonstrated, and the structure of DNA as a double helix clarified how genetic information is stored and replicated.

Nucleic acids are polymers built from nucleotides. Each nucleotide consists of a sugar (deoxyribose in DNA, ribose in RNA), a phosphate group, and a nitrogenous base. The backbone is formed by phosphodiester bonds, creating a sugar–phosphate chain. DNA bases pair specifically (adenine with thymine, cytosine with guanine) enabling a stable double-helix structure, while RNA is usually single-stranded and can fold into diverse shapes. The sugar–phosphate backbone is negatively charged, contributing to the solubility of nucleic acids in water.

Functions include storing hereditary information in the sequence of bases, replicating DNA for cell division, and directing protein synthesis via transcription (DNA to RNA) and translation (RNA to protein). Beyond coding sequences, diverse RNAs (rRNA, tRNA, miRNA, siRNA, lncRNA, etc.) participate in regulation and catalytic activities.

Nukleiini are essential to biology, medicine, and biotechnology, with applications in genetics, forensic science, sequencing, and therapeutics. In Finnish usage, nukleiini denotes nucleic acids as a whole, including both DNA and RNA.