Cis-syn thymidine dimers are used in DNA damage and repair research. One of the major causes of DNA damage is UV from sunlight that results in dimerization of adjacent pyrimidine bases, forming cyclobutane dimers (CPDs). The majority of CPDs are cis-syn cyclobutane thymidine dimers. If you are interested in incorporating a cis-syn thymidine dimer in an oligonucleotide please inquire for a custom quotation.