In vivo sister chromatid exchange frequencies in fetal and adult cells of mouse

Abstract

Sister chromatid exchange (SCE) frequencies in vivo in bone marrow and spleen cells of the adult and in the liver cells of fetal mice have been determined by bromodeoxyuridine (BrdU)-Giemsa staining technique. Analysis of SCEs in second cycle metaphases revealed that the mean SCE frequencies in adult bone marrow and spleen cells are 4.24 SCE/cell and 5.48 SCE/cell, respectively. In comparison, the fetal liver cells from the same animals show only 1.53 SCE/cell. It appears that the differences in the SCE frequencies in adult and fetal cells in vivo are due to different dosages of BrdU available to adult and fetal cells on account of placental barrier so that while in fetaI cells the basal level of spontaneous SCEs is seen, in the adult tissues some SCEs are induced by BrdU itself.