Reciprocal translocation in CML

Example of the reciprocal translocation t(9;22), which is a characteristic finding in chronic myelogenous leukemia (CML). A small, distal piece of chromosome 9 (indicated by the arrow in the left upper chromosome) is broken off and translocated to the distal chromosome 22, as illustrated by the derivative chromosome der (22)-. The chromosomal segment that was originally present in the normal chromosome 22 (below the arrow in the left lower chromosome) is translocated to the shortened chromosome 9 to form a derivative, large chromosome der (9)+.