nucleotidetriadet

Nucleotidetriadet, or nucleotide triplet, refers to a sequence of three nucleotides in DNA or RNA. In genetics, triplets are the basic units of the genetic code and, when transcribed and translated, are read as codons that specify amino acids or signal termination during protein synthesis.

In DNA, the four nucleotides are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, thymine is replaced by uracil (U). During transcription, a DNA triplet is copied into a complementary RNA triplet. During translation, ribosomes read the mRNA triplets in a non-overlapping reading frame, and transfer RNAs deliver the corresponding amino acids via anticodons that pair with the codons. The standard genetic code comprises 64 codons: 61 specify amino acids, and 3 are stop signals (UAA, UAG, UGA).

The code is nearly universal across organisms, though there are small variations in mitochondria and some microbes. It is degenerate, meaning most amino acids are encoded by more than one triplet. The third nucleotide often allows wobble base pairing, which reduces the number of tRNA species required while preserving translation accuracy.

Mutations within nucleotide triplets can alter codons and change amino acids, potentially affecting protein function. In addition, expansions of certain trinucleotide repeats—three-nucleotide sequences repeated many times—can cause genetic diseases, illustrating how nucleotide triplets influence biology beyond standard coding. See also codon, reading frame, genetic code, transcription, translation.