a thymidine(6-4)thymidine in DNA <=> a thymidine dimer in DNA
a thymidine(6-4)thymidine in dna <=> a thymidine dimer in dna
a thymidine(6-4)thymidine in DNA <=> a thymidine dimer in DNA
a thymidine(6-4)thymidine in dna <=> a thymidine dimer in dna