Frequency and distribution of sister chromatid exchanges in human peripheral lymphocytes.

The frequency and distribution of sister chromatid exchanges (SCE) were examined in a population of 10 normal individuals (five males and five females) and compared with those in patients with various numerical and structural chromosomal aberrations. Statistically significant differences within each group were observed among the normal subjects as well as among patients with similar cytogenetic aberrations. A consistent nonrandom distribution of SCE, with regard to chromosome length, was demonstrated, with a significant increase of SCE in the centromere region of some chromosomes.