Genes are understandably crucial to physiology, morphology and biochemistry, but the idea of genes contributing to individual differences in behavior once seemed outrageous. Nevertheless, some scientists have aspired to understand the relationship between genes and behavior, and their research has become increasingly informative and productive over the past several decades. At the forefront of behavioral genetics research is the fruitfly Drosophila melanogaster, which has provided us with important insights into the molecular, cellular and evolutionary bases of behavior. By employing this development in their experiments with laboratory fruit flies, Gantz and Bier demonstrated that by arranging the standard components of this anti-viral defense system in a novel configuration, a mutation generated on one copy of a chromosome in fruit flies spreads automatically to the other chromosome. The end result, Bier says, is that both copies of a gene could be inactivated “in a single shot.” The two biologists call their new genetic method the “mutagenic chain reaction,” or MCR. “MCR is remarkably active in all cells of the body with one result being that such mutations are transmitted to offspring via the germline with 95 percent efficiency. Thus, nearly all gametes of an MCR individual carry the mutation in contrast to a typical mutant carrier in which only half of the reproductive cells are mutant.” Bier says “there are several profound consequences of MCR. First, the ability to mutate both copies of a gene in a single generation should greatly accelerate genetic research in diverse species. For example, to generate mutations in two genes at once in an organism is typically time consuming, because it requires two generations, and involved, because it requires genetic testing to identify rare progeny carrying both mutations. Now, one should simply be able to cross individuals harboring two different MCR mutants to each other and all their direct progeny should be mutant for both genes.”
Ketamine—50 years in use: from anesthesia to rapid antidepressant effects and neurobiological mechanisms
