[Distribution of the frequency of sister chromatid exchange among Leningrad inhabitants].

Peculiarities of frequency variations in sister chromatid exchanges (SCE) were studied in a group of healthy Leningrad citizens who are not engaged in health-risk industries. No relations were found between the SCE frequency and sex, age and smoking habit (10 cigarettes per day as much). The statistical processing of the data obtained was made taking into account the errors in individual measurements of the SCE frequency. Repeated measurements revealed systematic and statistically significant variations in the rate of SCE.