Abstract
Comparative idiogram analysis was made in normal rat hepatic cells and cells of rat ascites hepatoma No. 7974. The idiogram of normal hepatic cells is characterized by 24 rod-type elements (including chromosomes with terminal or subterminal centromeres) and 18 V-type elements (including those with median or submedian centromeres), while the stemline idiogram of the hepatoma is remarkable by the presence of 48 chromosomes, among which 29 are of rod and 19 of V-type. There occur a dot-like element of the smallest size and a V-shaped elements somewhat larger than the other V-shaped ones.
Based on the idiogram comparison between the normal hepatic cells and the hepatoma cells, the conclusion may be possible that the hyperdiploid chromosome constitution of the present hepatoma may have arisen by duplication of some chromosomes and that the stem-cells with 48 chromosomes may have developed as a result of selection during serial transfers as having the best adaptability to the physiological conditions of the host.
