Individual Variability in the Frequency of Sister Chromatid Exchange in Human Lymphocytes

Abstract

Sister chromatid exchange (SCE) can be demonstrated in metaphase cells by autoradiographic techniques [1] or by more recently developed staining techniques [2]. Although the mechanism(s) and the nature of the alterations leading to SCE are largely unknown, there are a number of observations suggesting a relationship between mutagenic and/or carcinogenic damage and an increased rate of SCEs [3]. Firstly there is a linear correlation between the induction of SCE and single gene mutation for many chemical agents, and both of these events show a similar spontaneous rate of occurrence over the entire genome [4]. Secondly, a great number of mutagens and carcinogens have been shown to induce SCEs, in some cases at very low concentrations, in various mammalian cellsin vitro as well asin vivo [5, 6]. Finally, the induction of SCE is S-phase dependent, and appears to be closely related to DNA replication [3].