KANSAS CITY, MO Cells trying to keep pace with constantly changing environmental conditions need to strike a fine balance between maintaining their genomic integrity and allowing enough genetic flexibility to adapt to inhospitable conditions. In their latest study, researchers at the Stowers Institute for Medical Research were able to show that under stressful conditions yeast genomes become unstable, readily acquiring or losing whole chromosomes to enable rapid adaption.
The research, published in the January 29, 2012, advance online issue of Nature, demonstrates that stress itself can increase the pace of evolution by increasing the rate of chromosomal instability or aneuploidy. The observation of stress-induced chromosome instability casts the molecular mechanisms driving cellular evolution into a new perspective and may help explain how cancer cells elude the body's natural defense mechanisms or the toxic effects of chemotherapy drugs.
"Cells employ intricate control mechanisms to maintain genomic stability and prevent abnormal chromosome numbers," says the study's leader, Stowers investigator Rong Li, Ph.D. "We found that under stress cellular mechanisms ensuring chromosome transmission fidelity are relaxed to allow the emergence of progeny cells with diverse aneuploid chromosome numbers, producing a population with large genetic variation."
Known as adaptive genetic change, the concept of stress-induced genetic variation first emerged in bacteria and departs from a long-held basic tenet of evolutionary theory, which holds that genetic diversityevolution's raw material from which natural selection picks the best choice under any given circumstancearises independently of hostile environmental conditions.
"From an evolutionary standpoint it is a very interesting finding," says graduate student and first author Guangbo Chen. "It shows how stress itself can help cells adapt to stress by inducing chromosomal instabilit
|Contact: Gina Kirchweger|
Stowers Institute for Medical Research