DNA damage repair in the skin of adult zebrafish. Fish were exposed to UVB (2.16 kJ/m2) light; photoproducts frequencies at 0, 3, 6, and 24 h postirradiation were quantified using radioimmunoassay and normalized to the amount of damage present immediately after UVB exposure in wt zebrafish (100%). DNA repair in wt and p53 mutant fish was determined and compared for (A) the repair of (6-4)PDs and (B) the repair of cyclobutane pyrimidine dimers. (C) Comparison of cyclobutane pyrimidine dimers repair rate at 24 h postirradiation in wt zebrafish and three Xiphophorus species: X. couchianus, X. maculates, and X. andersi.