Molecular Characterization of 15 Rearrangements among 90 Human In Vivo Somatic Mutants Shows that Deletions Predominate

Abstract

Ninety hypoxanthine phosphoribosyltransferase-deficient mutants were isolated from lymphocytes of 31 individuals drawn from both control populations and populations exposed to low doses of ionizing radiation. Southern analysis of the DNA revealed altered hybridization patterns in 15 mutants. Of these, 14 changes consisted of deletions of 2 to 40 kilobases or more.

Homologous Plasmid Recombination Is Elevated in Immortally Transformed Cells

“…Most carcinogens prove to be mutagenic when assayed in Salmonella Hisreversion assays which are specific for point or frameshift mutations (6), but many are poorly detected by such mutation assays, resulting in concordances of -60% (23,46). It has been argued that DNA rearrangements are strongly implicated, perhaps even more than point mutations, in carcinogenesis (6,30,51,53), a view supported by the remarkably large fraction of spontaneous somatic mutations which are DNA rearrangements, primarily deletions (9).…”