Fruit Flies

As one northern Michigan expert has discovered, they’re a lot like us.

By Craig Manning | Sept. 16, 2017

When September comes to northern Michigan, it never comes alone. Along with its bushels of apples, peaches, and tomatoes, September never fails to bring a bounty of altogether different kind of fruit: the infuriating fruit fly … and, generally, 6,000 or so of its cousins. If you have a kitchen Up North, no doubt you’ve spent at least a few warm falls waging war against these pesky pests. Thomas Werner, however, has done just the opposite. For this assistant professor of biological sciences at Michigan Tech University, fruit flies aren’t a source of annoyance. On the contrary, he sees them as an opportunity for scientific discovery.

Werner recently worked with University of Rochester professor John Jaenike to coauthor a book dedicated entirely to the appreciation of fruit flies. The book, “Drosophilids of the Midwest and Northeast,” is an extensive compendium of knowledge about the much-maligned fruit fly. It includes details about 55 different species, as well as full-color photographs that Werner took himself, using a $35,000 Michigan Tech microscope.

For Werner, the book is the culmination of a decades-long career researching fruit flies — a specialty that has taken him a long way from home. From universities in Germany and Sweden to the lab of celebrated biologist Sean Carroll at the University of Wisconsin in Madison, all the way to Michigan Tech, Werner has built a life around studying what, for many, is just a pesky plague of summer.

Werner’s work with fruit flies has brought him much success and renown — including published papers in both Nature and Science, two of the top scholarly scientific journals in the world — but he initially fell into the field as a compromise. Born and raised in East Germany, Werner started collecting butterflies at age 10. When he arrived at university, his intention was to take his fascination with butterflies to the scholarly level. But when a friend bluntly told him that a specialty in butterflies would “lead to unemployment,” he switched lanes, studying general molecular biology instead.

Time and time again throughout his career, Werner found that, despite their beauty, butterflies held no real value in the research community — meaning no university was keen to fund butterfly research or pay a scientist to conduct it. Fruit flies though, were a different story—not because of their beauty (or lack thereof), but because of their genetic makeup.

“The fruit fly shares about 60 to 70 percent of the same genes that humans have,” Werner said. “So the fruit fly is a very important model organism that goes much cheaper and much faster for investigating human diseases. When you look back at human diseases, most of the genes that cause human diseases, they were discovered first in fruit flies. This is because we are pretty similar to fruit flies when we look at our genetic setup.”

So far, Werner has been a part of several major discoveries in fruit fly genetics. While working toward his PhD at Umea University in Sweden, he studied the innate immune response in fruit flies. That work led to the discovery of a new family of genes that encode proteins and recognize peptidoglycan, the polymer found in the cell wall of most bacteria. One Science article later, he was at the University of Wisconsin, where his mentor took pity on his desire to study butterflies and gave him the next best thing.

“He said, “Here is a beautiful fruit fly species. It looks like a butterfly almost because it has pretty spots on the wings. Do you want to take the challenge and work with this non-model organism, and either kill your career or become very famous?’”

Werner took the plunge and hoped for the best. For the next five years, he studied the unique fruit fly species, trying to figure out what caused those butterfly-like spots on the wings. What he discovered was another career game changer.

“The gene that triggers the spot formation on the wings is also a very famous — or infamous — cancer gene in humans,” Werner said. “Humans and flies share the gene, and in humans, it causes about 70 percent of cancers. It’s overactive and it causes cells to divide and tumors to grow large and massive. But in fruit flies, this same gene has actually learned a new trick and gotten involved in the pigmentation process. It has basically taken the pigmentation process under its control, and then triggered the development of black spots on the wings, and they just look very beautiful.”

This time, Werner’s research landed on the cover of Nature and send him toward the assistant professorship he now holds at Michigan Tech. But it also showed him how much potential there was for fruit fly research in unusual, non-model species. So far, most fruit fly research has centered around the common fruit fly, drosophila melanogaster. By looking at other types of fruit flies, Werner thinks the scientific community could learn a lot more about genetics and human diseases. The challenge, he says, is in the identification of those non-model organisms.

Therein lies the value of Drosophilids of the Midwest and Northeast. The book, with its detailed images of different species and easy-to-understand notes and descriptions, is an invaluable aid to anyone trying to move beyond the common fruit fly for genetic research. By pairing Werner’s images and scientific background with Jaenike’s depthless knowledge of different species — Jaenike can identify and distinguish fruit fly species with the naked eye — the book provides perhaps the most comprehensive overview ever published on non-model fruit fly species.

“The fruit fly drosophila melanogaster has been worked on for 120, 130 years now,” Werner said. “You can only study so many things in this fruit fly species. If you want to study other traits, behavior, ecology of fruit flies, you have to move out of this drosophila melanogaster. With our book, researchers can find the species of interest they want to study, learn how to breed it, how to collect it, and how to attract it. And then they can actually start working with new fruit fly species and answering new questions about evolution, development, and ecology.”

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“Drosophilids of the Midwest and Northeast” is currently available as a free e-book download on the University of Rochester website. It can be found at http://humanities.lib.rochester.edu/drosophilaguide.