A STUDY ON THE CLONAL NATURE OF SPLEEN COLONIES USING CHROMOSOME MARKERS

Abstract
Cytological evidence for the clonal origin of spleen colonies is presented. Karyotypic analysis of the spleen nodules produced by transplants of hematopoietic tissue from radiation chimeras bearing 3 kinds of chromosome-marked cells showed 41 out of 48 spleen nodules to be composed entirely of one or another of the karyotypes. In the remaining 7 nodules 92 to 98% of the dividing cells in each nodule were of the same type. Since no mixtures were observed in proportions consistent with other than single cell origin, the data lend further support to the clonal hypothesis of origin of the spleen colony.