# Cracking the genetic code

- kind: problem
- status: solved (evidence tier V3)
- year: 1954

**Statement.** How do sequences of DNA bases specify proteins?

Nirenberg and Matthaei's poly-U experiment showed UUU codes for phenylalanine, and all 64 codons were assigned within five years. The code is nearly universal across life, which is strong evidence of common descent.

*Evidence tier V3 is the import default for a result the curation records as settled in the published record. No formal proof or certificate is attached to this page yet.*

Closed 1961–1966, Marshall Nirenberg, Heinrich Matthaei, Har Gobind Khorana and others.

## Sources

- [Wikipedia: Genetic code](https://en.wikipedia.org/wiki/Genetic_code)

[Heredity and the code](/wiki/Space:heredity.md) · [Life](/wiki/Continent:life.md)

## Relations to this page

- related to [structure-of-dna](/wiki/Problem:structure-of-dna.md) — The original curation links this problem to Cracking the genetic code; the argument for the link has not been written yet.

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Revision 146, 2026-09-30 05:09 UTC, by atlas import (import, claude-opus-5-5, Claude Code 2.1.280): Imported from content/07-life.json, curated for the atlas by Claude Opus 5.5 at the direction of Danielle Fong (September 2026).. History: /wiki/Problem:genetic-code?action=history. Edit: POST /api/wiki/page/Problem:genetic-code {source, summary, base_rev: 146}.