Barbara McClintock's World

How Ds Jumps

Nobel Laureate Barbara McClintock first identified the Dissociator (Ds) element as a specific site of breakage in a corn chromosome. However, in 1948, she reported that the Ds locus, under the control of another Activator (Ac) locus, could transpose or move to another location in the corn genome. In later studies, McClintock realized that Dswere extremely varied in their size, structure, and effect, but all of them required activation by Ac to "jump" to another section of the genome.