Mutant Screens

Doctor Josh Dubnau explains that mutant screens generate a large panel of mutant animals that average a mutation in one gene. Each animal is then tested for a particular characteristic.

Mutant screening is a way that geneticists use to find the building blocks of a particular biological process. So the assumption of a mutant screen is that the basic instructions in the chromosomes, in the genes, will play a role in building a particular biological process. It could be building the structure of the eye; it could be telling the embryo which end is going to be the head and which end will be the tail, or it could be wiring the brain in such a way that it can learn. And a mutant screen is done by randomly perturbing genes, usually with chemicals that disrupt chromosomes, and generating a huge panel of mutant animals, each of which on average has a mutation in one gene and then systematically, laboriously testing each of those animals for whatever the characteristic is we’re interested in, and we call those characteristics phenotypes. In the case of memory, we would generate a panel of thousands of animals, each of which had a mutation in one gene, and carefully measure the behavior of the animal in a way that told us how well that animal could learn and remember a particular experience. And we would find the individual flies that had mutations in individual genes that impacted the abilities of that animal, and then try to identify what those genes are.