Preparation and identification of partially fractionated Chinese hamster chromosomes

Mitotic Chinese hamster chromosomes were isolated from synchronized, cultured M3-1 cells by hypotonic swelling followed by homogenization. The chromosomes were then fractionated by size by sucrose gradient sedimentation centrifugation. The resolution of the fractionation was determined by studying the morphology and Giemsa-banding patterns of the chromosomes found in each fraction. Fractions were obtained which were composed of as much as 50% of one chromosome type. Preparations such as these can be used for large scale physicochemical studies of single chromosome types.