3H-thymidine-induced chromosome aberrations in cultured human leukocytes

Abstract

Short-term human leukocyte cultures from two individuals with different cytological backgrounds were treated with ³H-thymidine. Gaps, deletions, fragments and translocations were observed. The two cases responded much differently probably owing to differences in genetic background. Using autoradiographic procedures, it was observed that aberrations arise more or less in equal frequency in the synthesizing regions of chromosomes as in regions which had completed DNA synthesis. Gaps are attributed to subchromatid breaks and are randomly located, i.e., not necessarily restricted to late-replicating, heterochromatic regions.