[Various banding simultaneously obtained on the same slides, after treatment by BrdU (author's transl)].

A treatment by BrdU during 24 hrs, followed by a treatment by thymidine, during 30 hrs, induces in the same preparations, many types of chromosome banding R-, Q-, H-bands, and several types of asymmetry. This indicates that the BrdU is not incorporated only in some parts of the karyotype, but, on the contrary, any where, and then induces different banding according to the site of its incorporation. Above all, the type of band is determined by the period of the phase S in which the cell was at the time of the treatment by BrdU. Thus the coexistence of many types of banding may be explained here by the great variability of the cellular cycle of the lymphocytes in culture.