pyrimidine dimermedical dictionary

<biochemistry> A dimer product found in DNA chains damaged by ultraviolet irradiation. Most frequently thymidine dimers.

They consist of two adjacent pyrimidine nucleotides, usually thymine nucleotides, in which the pyrimidine residues are covalently joined by a cyclobutane ring. These dimers stop DNA replication.

(21 Jun 2000)