Chromosome Aberrations in Liver Cells in Relation to the Somatic Mutation Theory of Aging

Abstract

The percentage of cells containing chromosomal aberrations present in regenerating liver of mice has been scored as a function of (1) age in normal mice, (2) age for mice subjected to chronic [gamma]f -irradiation, (3) time after a single dose of X-rays and (4) time after a single dose of neutrons. Normal mice develop chromosomal aberrations linearly with age, and mice subjected to chronic [gamma]y -irradiation develop them at a greater rate. In comparing acute X-irradiation with chronic [gamma]-irradiation, it is apparent that chromosome aberrations result from multihit events; in other words, chromosome healing is possible after small doses. Chromosomal damage seems more severe for neutrons than for X-rays for equal acute damage, and recovery from neutron irradiation is much slower. These results strongly support the somatic mutation theory of aging, and it is concluded that this theory alone can explain the known facts of aging and radiation-induced aging.