so as shown on the visual, thomas hunt morgan used the vinegar fly to show that genes are arranged in a linear sequence on chromosomes. we now know that genes are made of d.n.a. that beautiful double helix structure discovered by watson and crick. and what seymour benzer did in the '60s is he took this wealth of genetics in the fly and showed that you could use it to study how genes control simple behaviors like attraction to light. >> this was the first time one had a genetic handle on various behaviors. >> right. so it turns out you can study emotion like behavioral expression in flies just like other animals. so the two most common expressions of fear are freezing and running or flight. and so as we can see in this this this video, flies show a freezing like reaction when they're confronted by a dangerous stimulus, in this case the wind which could threaten to blow them away. they freeze, now whether they are experiencing some internal state we can't say. they may just be clinging on for dear life or they may have something more complicated going on but we can study this behavioral

basic fruit fly so the fruit fly was really used and developed as an experimental organizism by thomas hunt morgan at columbia university. and he was interested in basic aspects of chromosome and heredity. later see more benzer he opened up the world of the brain and the fly and he focused on genes that were involved in behavior. and just like malion talked about there are regions of the brain that are isolated, but they also connect to other regions of the brain, greens don't work on their own but genes work in a network with other genes. and these are called gene pathways. so in fact we now know that for many process cease not only genes but entire gene pathways are shared between flies and humans. so that means that he with can then take that gene and study it and ask how it may be functioning. and hope to learn not only about flies but really what we are interested in. we're interested in people, in humans. right. and so this, the fly has been classically used to approach development and then it's more recently become very popular for behavior. and we decided well, why not try with human disea