Why Are Fruit Flies Science Superstars?

Fruit flies are pests in our kitchens but glorious in genetics labs. Learn why -- and why they're not dangerous, even if they're annoying -- in this episode of BrainStuff.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, Lauren vogebam here. If you've ever swatted it
fruit flies hovering over the fruit bowl on your kitchen
counter and wondered what purpose they could ever possibly serve humanity,
You're not alone. They are small, and they are annoying,
but humans owe them a huge debt of gratitude for

(00:23):
their contributions to the science of modern genetics. One species,
in particular, Drosophila melanogaster, is a superstar of tiny, annoying
winged things. At least five Nobel Prizes have been awarded
to scientists for their work on fruit flies. Yes, the
lowly fruit fly and the larger, glorious er human have

(00:44):
together tackle genetics and done a lot of cool stuff.
But like why fruit flies? And how do you keep
them out of your kitchen? And do we need to
blame scientists for them being in your kitchen? To begin with,
fruit flies have been used in biological studies for a
long time, which means there are a lot of tools
and resources for scientists using Drosophila melanogaster to ask interesting questions.

(01:09):
But there are some specific reasons. The species has always
been a Darling of geneticists. For starters in genetics, it's
helpful to have research subjects that can cycle through generations
rather quickly, and fruit flies are great at that. We
spoke via email with Thomas Merritt, PhD, Professor in the
Department of Chemistry and Biochemistry at Laurentian University in Ontario, Canada.

(01:32):
He said fruit flies create a new generation in about
two weeks, making breeding them in the lab simple. They're
also small and easy to rear and care for, and
it's easy to house as many of them as you
need in a single lab at one time. Also, fruit
flies are surprisingly similar to humans and other vertebrates. Drosophila
melanogaster has fourteen thousand genes, and we humans have somewhere

(01:55):
between twenty thousand and twenty five thousand, and about eight
thousand of those vans are analogous. Similarly, most fruit fly
biochemistry is the same or similar to ours. Merritt said
fruit flies are great to work on if you're interested
in variation between individuals or genetic lineages. They are also
a great system if you're interested in experimentally altering the environment.

(02:18):
They are so small we can do things like keep
thousands of flies at different temperatures to see how temperature
changes metabolism or gene activity. In one study in my lab,
we used a small conveyor belt to slowly turn the
vials we keep the flies in. This simple instrument is
essentially a fly treadmill, and we can get literally hundreds
of flies exercising on a small desktop. But fruit flies

(02:42):
can be annoying in a lab, just as they can
in your kitchen, to begin with their small and it's
very difficult to dissect a fruit fly in case you
were wondering. And although we share many of the same
genes and genetic networks, were separated from them by hundreds
of millions of years of evolution. So it's hard to
make assumptions about ourselves based on what we find in

(03:03):
these little insects because there are substantial biological differences between us.
Merritt said, there are certainly questions that are better asked
in larger or evolutionarily more closely related species like rats
and mice. Similarly, there are questions, for example, changes in
genes through evolution that are better asked in organisms that
are even smaller, can be kept in even larger numbers,

(03:26):
and with even shorter lifespans like bacteria or fungi. But
we can't blame scientists for the proliferation of fruit flies
in the world. They would have been there regardless, Merrett explained.
Drosophalo melanogaster is a cosmopolitan species, meaning it's found essentially
almost anywhere we find humans. A fruit fly has pretty

(03:48):
simple needs in order to prosper and multiply, and those
needs are usually met in our homes, moderate temperatures and
a source of fresh produce that's on the overripe side.
This is why fruit flies live i on the hug
in places like dumpsters, compost tapes, and kitchens. Marrett said.
One interesting thing is we seem to see more flies

(04:08):
inside in the early fall. I think that's from flies
that have been happily breeding and multiplying outside all summer
moving into the warmer inside spaces as the weather cools.
The good news is that fruit flies aren't dangerous in
any way. Merritt said. They don't carry disease, and they
don't cause fruit to spoil or rot. At least Drosophila

(04:30):
melano gaster doesn't, although there is at least one invasive species,
the spotted wing fruit fly that actually damages fruit crops,
and it's a growing agricultural concern. In my lab and
in my house, we use a simple vinegar trap kenning
jar with some vinegar in the bottom and a top
of plastic wrap with a few holes punched in it
to trap and remove flies. Today's episode was written by

(04:57):
Joceline Shields and produced by Tyler Clang. For more on
this and lots of other tiny topics with a huge impact,
visit how stuff works dot com. Brain Stuff is production
of iHeart Radio. For more podcasts for my heart Radio,
visit the iHeart Radio app, Apple Podcasts, or wherever you
listen to your favorite shows.