Nav: Home

Researchers discover gene in fruit flies that explains how 1 species evolved into 2

December 17, 2015

SEATTLE - Evolutionary biologists at Fred Hutchinson Cancer Research Center, University of Washington and the University of Utah may have solved a century-old evolutionary riddle: How did two related fruit fly species arise from one?

Researchers have helped answer this question through the discovery of a gene responsible for dividing two species of fruit flies. The existence of this mysterious gene had been guessed at since 1910, when geneticists first noticed that the two types of flies, when mated, had only daughters - and no sons. The definition of a species is that it cannot breed successfully with another species; understanding these reproductive barriers is key to understanding speciation.

The findings, published Friday in Science, arose from a collaboration of the laboratories of evolutionary biologist Dr. Harmit Malik, a member of the Basic Sciences Division at Fred Hutch, and fly geneticist Dr. Nitin Phadnis, assistant professor and Mario R. Capecchi Endowed Chair in Biology at the University of Utah.

Malik and Phadnis first met to brainstorm the experiment that would solve this evolutionary conundrum when Phadnis was a postdoctoral fellow in Malik's Fred Hutch lab. The researchers planned to mutate one of the fly species in the hopes of randomly disrupting the mystery gene and thus allowing males to be born.

Because they knew the flies would have many other mutations sprinkled throughout their genome, they calculated that they'd need to find seven rare male flies to conclusively pinpoint the mystery gene's identity. From that point, the scientists jokingly referred to the elusive sons as the seven samurai, after the classic Akira Kurosawa film of the same name.

The researchers estimated the seven samurai experiment would take about six months of mutating, mating and examining the tiny insects. Six months later, they'd found no male flies. About a year after that, however, after mating some 55,000 mother and mutant father pairs, the researchers sifted through 330,000 daughter flies and found six precious sons.

They never did find their seventh samurai, but it turned out they didn't need to. In collaboration with colleagues at the University of Washington, Malik and Phadnis found that all six males had mutations in the same gene, meaning they'd found what they were seeking.

Known as gfzf, this cell-cycle checkpoint gene is important for regulating how cells progress through division. For these particular fly species, Drosophila melanogaster and Drosophila simulans, it appears to also play a role in speciation - how one species evolves into two.

The discovery that gfzf causes death or infertility in fruit fly hybrids "is really important in cancer biology," Phadnis said. "Cancer biologists are interested in cell cycle checkpoints because you can get cancer when those go bad [and cells proliferate uncontrolled]. Biologists want to understand the machinery. This work shows that some of those components in the cell-cycle policing machinery may be quickly changing."

Added Malik: "Cell-cycle policing by genes like gfzf plays important roles in correcting errors in the cell cycle that could result in cancers if left uncorrected. Our work suggests that speciation and cancer biology may be part of the same continuum of biological processes."

The problem of speciation has vexed evolutionary biologists for more than 100 years, but it's only with the advent of modern molecular tools that finding this gene was possible, Malik said.

"There was no way to use a traditional genetics approach. We needed a totally new, genomics-based approach to understand this," said Malik, also a Howard Hughes Medical Institute investigator. "So at the heart it's a genetics problem, but traditional genetics can't solve this problem."

Now that the researchers have figured out the solution to this single speciation event, they think their technique could be used to solve many other riddles of how species arise - as long as those species are small enough to study by the tens or hundreds of thousands in the lab, Malik said.
This work was funded in the Malik Lab by grants from the National Institutes of Health, Howard Hughes Medical Institute and the G. Harold & Leila Y. Mathers Foundation.


At Fred Hutchinson Cancer Research Center, home to three Nobel laureates, interdisciplinary teams of world-renowned scientists seek new and innovative ways to prevent, diagnose and treat cancer, HIV/AIDS and other life-threatening diseases. Fred Hutch's pioneering work in bone marrow transplantation led to the development of immunotherapy, which harnesses the power of the immune system to treat cancer with minimal side effects. An independent, nonprofit research institute based in Seattle, Fred Hutch houses the nation's first and largest cancer prevention research program, as well as the clinical coordinating center of the Women's Health Initiative and the international headquarters of the HIV Vaccine Trials Network. Private contributions are essential for enabling Fred Hutch scientists to explore novel research opportunities that lead to important medical breakthroughs. For more information visit or follow Fred Hutch on Facebook, Twitter or YouTube.

Fred Hutchinson Cancer Research Center

Related Cancer Articles:

Radiotherapy for invasive breast cancer increases the risk of second primary lung cancer
East Asian female breast cancer patients receiving radiotherapy have a higher risk of developing second primary lung cancer.
Cancer genomics continued: Triple negative breast cancer and cancer immunotherapy
Continuing PLOS Medicine's special issue on cancer genomics, Christos Hatzis of Yale University, New Haven, Conn., USA and colleagues describe a new subtype of triple negative breast cancer that may be more amenable to treatment than other cases of this difficult-to-treat disease.
Metabolite that promotes cancer cell transformation and colorectal cancer spread identified
Osaka University researchers revealed that the metabolite D-2-hydroxyglurate (D-2HG) promotes epithelial-mesenchymal transition of colorectal cancer cells, leading them to develop features of lower adherence to neighboring cells, increased invasiveness, and greater likelihood of metastatic spread.
UH Cancer Center researcher finds new driver of an aggressive form of brain cancer
University of Hawai'i Cancer Center researchers have identified an essential driver of tumor cell invasion in glioblastoma, the most aggressive form of brain cancer that can occur at any age.
UH Cancer Center researchers develop algorithm to find precise cancer treatments
University of Hawai'i Cancer Center researchers developed a computational algorithm to analyze 'Big Data' obtained from tumor samples to better understand and treat cancer.
New analytical technology to quantify anti-cancer drugs inside cancer cells
University of Oklahoma researchers will apply a new analytical technology that could ultimately provide a powerful tool for improved treatment of cancer patients in Oklahoma and beyond.
Radiotherapy for lung cancer patients is linked to increased risk of non-cancer deaths
Researchers have found that treating patients who have early stage non-small cell lung cancer with a type of radiotherapy called stereotactic body radiation therapy is associated with a small but increased risk of death from causes other than cancer.
Cancer expert says public health and prevention measures are key to defeating cancer
Is investment in research to develop new treatments the best approach to controlling cancer?
UI Cancer Center, Governors State to address cancer disparities in south suburbs
The University of Illinois Cancer Center and Governors State University have received a joint four-year, $1.5 million grant from the National Cancer Institute to help both institutions conduct community-based research to reduce cancer-related health disparities in Chicago's south suburbs.
Leading cancer research organizations to host international cancer immunotherapy conference
The Cancer Research Institute, the Association for Cancer Immunotherapy, the European Academy of Tumor Immunology, and the American Association for Cancer Research will join forces to sponsor the first International Cancer Immunotherapy Conference at the Sheraton New York Times Square Hotel in New York, Sept.

Related Cancer Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".