Why Fruit Fly Research is No Joke


Drosophila Melanogaster, the common fruit fly (credit: Ed Dougherty)

Did you know that researchers are learning valuable information about human genetics, sleep, and even disease by studying …fruit flies?

April Fool’s? Absolutely not! While the idea that studying fruit flies can teach us about human biology might sound pretty far out, they are just one of the many model organisms used by researchers around the world every day. We talked to Northwestern University associate professor of neurobiology and physiology Ravi Allada to find out why fruit fly studies are no joke.

Ravi Allada (Photo by Rick Gaber)Ravi Allada (Photo by Rick Gaber)First of all, what are model organisms, and why are they so important to research?
Model organisms, like fruit flies and worms, are used because they have much simpler systems, which are easier to study and manipulate, but they still replicate aspects of biology in more complex systems, even those of humans.

There are also a number of technical advantages. You can study a large numbers of flies fairly inexpensively, and they have short generation times. This means that you can observe a fly’s entire lifespan in just a few weeks, and generations of flies in a few months. Model organisms are especially useful for genetic studies, because you can screen for thousands of genes (units of genetic information that code for specific functions) in thousands of flies much faster and less expensively than in mammals.

Why do fruit flies serve as good models for humans?
Many of the genes present in fruit flies, also known as Drosophila, are conserved in humans. This means that genes often serve similar functions in Drosophila as they do in humans. For example, Drosophila produces molecules similar to insulin. Loss of insulin results in elevated blood sugar levels like those seen in diabetics. This allows researchers to study the mechanisms of this disease and even possible treatments using model organisms.

Why did you start working with Drosophila?
One of my first projects as a researcher used Drosophila to study anesthesia. General anesthetics have been used for more than 150 years, but we still don’t know exactly how these compounds work. Because Drosophila respond to similar concentrations of anesthesia as humans do, they can help us study how anesthesia affects consciousness. My lab is currently working on genes in flies that are important for responding to isoflurane, a common anesthetic.

Another focus of my lab is investigating why we sleep using Drosophila as a model.

Do flies really sleep?
Yes, really. They exhibit all of the behaviors that we associate with sleep—they stop moving, become unresponsive to stimuli, and so on. In fact, if you deprive a fly of sleep one day, it will try to make up for it the next. So why do we all need sleep? This is the big question. And a better understanding the mechanisms behind sleep will help answer it.

What have you learned?
We’ve studied flies to determine what neural circuits influence how much they sleep. It turns out that these circuits are associated with learning and memory too. One idea that we and others are pursuing is that when we’re awake, we’re constantly taking in new information, we’re learning all day. This strengthens the synapses (connections between neurons) in our brains, but at some point they reach saturation and need sleep to “reset.” Our data suggest that when our brains have learned enough (or too much), these neural circuits tell the body to shut down, or go to sleep.


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