A thymidine analog that can be incorporated into DNA during its replication. This substitution profoundly affects that structure of the DNA. When both strands are substituted with BUDR, a chromatid stains less intensely than when only one strand is so substituted. Thus when cells are grown in the presence of BUDR for two replication cycles, the two sister chromatids stain differentially and therefore are called harlequin chromosomes. Consequently, the BUDR labeling method can be used to detect sister chromatid exchanges. BUDR causes breakage in chromosomal regions rich in heterochromatin. Additional acronyms are Budr and Brdu. See Chronology, 1972, Zakharov, and Egolina.
Subjects: Genetics and Genomics.