Spontaneous chromosomal aberration levels in human peripheral lymphocytes.

Spontaneous levels of structural chromosomal aberrations in human peripheral lymphocytes were studied cytogenetically in 49 female and 56 male subjects. With a total of 16 267 metaphase spreads examined, 191 cells were found to contain chromosomal aberrations, giving a rate of 1.17%. The rates of individual aberration types were as follows: chromatid fragments, 0.39%; chromosome fragments, 0.71% dicentrics, 0.06%; symmetrical and asymmetrical chromatid exchanges, 0.01%; and rings, 0.006%. There were significant differences in aberration yields between females aged 20--29 yr. and 60--70 yr., whereas males aged 20--50 yr. showed no difference. The two sexes differed significantly in chromatid fragments, chromosome fragments and aberrants cells.