translocation /-lōkā″shən/ [L, trans + locus, place] , the rearrangement of DNA within a chromosome or the transfer of a segment of one chromosome to a nonhomologous one. In simple translocations, an end segment of one chromosome is transferred onto the end of another, involving a single break in only one of the chromosomes. Translocations in which material from the middle of one chromosome is shifted to the middle of another one are more complex and involve at least three breaks in the participating chromosomes. Such shifting of genetic material can result in serious disorders, such as Down syndrome, which can be caused by a 14/21 translocation, and chronic granulocytic leukemia, in which part of the long arm of chromosome 22 is translocated to the short arm of chromosome 9. Kinds include balanced translocation, reciprocal translocation, robertsonian translocation.
