genetic code n.
The sequence of nucleotides that is the basis of heredity in the DNA molecule of a chromosome and that specifies the amino acid sequence in the synthesis of proteins.
|genetic code |
The sequence of nucleotides in DNA and RNA that serve as instructions for synthesizing proteins. The genetic code is based on an "alphabet" consisting of sixty-four triplets of nucleotides called codons. The order in which codons are strung together determines the order in which the amino acids for which they code are arranged in a protein.
The code that translates the sequence of nucleotides in genes along the DNA strand into the structure of protein, which, through its action as an enzyme, governs one chemical reaction in the cell. A simple mnemonic is “One gene codes for one protein which runs one reaction.”
Note: All living things share the same genetic code, a fact that represents strong evidence for evolution. Unraveling the genetic code was one of the great scientific achievements of the twentieth century, and it opened the way to genetic engineering.