B-A Translocation Manipulation

Abstract

B-A translocations have unique properties that distinguish them from standard (A-A) translocations. One of these is the capacity for nondisjunction. Standard B chromosomes undergo nondisjunction very frequently at the second pollen mitosis. In B-A translocations, the chromosome with the B centromere acquires this property. Therefore, B^A chromosomes show dosage variation when transmitted through the pollen. B-A translocated chromosomes are usually designated in the form B^A or A^B. The superscripts denote the arm without its centromere.

The classical terminology for B-A translocations is used in this chapter. The chromosome listed first carries the centromere; the second chromosome (an arm donor) is written as a full-sized superscript character, i.e., B^A or A^B. New terminology has been proposed that will probably render superscripts obsolete (B^A becomes B-A). When a final decision is reached, the new “rules” will be published in the Maize Genetics Cooperation News Letter. The Editors