THE SOMATIC CHOMOSOMES OF MAN

Abstract

Human chromosomes were analyzed from cells which originated in a variety of organs of 13 different individuals and which were grown in vitro under carefully controlled conditions. Exact counts were performed on almost 2000 cells, of which 99.9% revealed chromosome numbers of 46 or 92, the tetraploid frequency being less than 3%. The individual chromosomes were characterized on the basis of their size, position of the centromere, and possession of a satellite and were assigned to 8 different groups. The sex chromosomes were identified and the X shown to be approximately 3 times larger than the Y.