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W. Richard McCombie

A Jamaican fruit bat, one of two bat species Scheben studied as a part of his comparative genomic work. Photo by Brock & Sherri Fenton

By Daniel Dunaief

Popular in late October as Halloween props and the answer to trivia questions about the only flying mammals, bats may also provide clues about something far more significant.

Despite their long lives and a lifestyle that includes living in close social groups, bats tend to be resistant to viruses and cancer, which is a disease that can and does affect other mammals with a longer life span.

Armin Scheben

In recent work published in the journal Genome Biology and Evolution, scientists including postdoctoral researcher at Cold Spring Harbor Laboratory and first author Armin Scheben, CSHL Professor and Chair of the Simons Center for Quantitative Biology Adam Siepel, and CSHL Professor W. Richard McCombie explored the genetics of the Jamaican fruit bat and the Mesoamerican mustached bat.

By comparing the complete genomes for these bats and 13 others to other mammals, including mice, dogs, horses, pigs and humans, these scientists discovered key differences in several genes.

The lower copy number of interferon alpha and higher number of interferon omega, which are inflammatory protein-coding genes, may explain a bat’s resistance to viruses. As for cancer, they discovered that bat genomes have six DNA repair and 33 tumor suppressor genes that show signs of genetic changes.

These differences offer potential future targets for research and, down the road, therapeutic work.

“In the case of bats, we were really interested in the immune system and cancer resistance traits,” said Scheben. “We lined up those genomes with other mammals that didn’t have these traits” to compare them.

Scheben described the work as a “jumping off point for experimental validation that can test whether what we think is true: that having more omega than alpha will develop a more potent anti-viral response.”

Follow up studies

This study provides valuable potential targets that could help explain a bat’s immunological superpowers that will require further studies.

“This work gives us strong hints as to which genes are involved, but fully understanding the molecular biology will require more work” explained Siepel.

In Siepel’s lab, where Scheben has been conducting his postdoctoral research since 2019, he is using human cell lines to see whether adding genetic bat elements makes them more effective in fighting off viral infections and cancer. He plans to do more of this work with mice, testing whether these bat variants help convey the same advantages in live mice.

Armin Scheben won the German Academic International Network Science Slam competition with his presentation on bat genomics.

Siepel and Scheben have discussed improving the comparative analysis by collecting information across bats and other mammals of tissue-specific gene expression and epigenetic marks which would help reveal changes not only in the content of DNA, but also in how genes are being turned on and off in different cell types and tissues. That could allow them to focus more directly on key genes to test in mice or other systems.

Scheben has been collaborating with CSHL Professor Alea Mills, whose lab has “excellent capabilities for doing genome editing in mice,” Scheben said.

Scheben’s PhD thesis advisor at the University of Western Australia, Dave Edwards described his former lab member’s work as “exciting.”

Edwards, who is Director of the UWA Centre for Applied Bioinformatics in the School of Biological Sciences, suggested that Scheben stood out for his “ability to strike up successful collaborations” as well as his willingness to mentor other trainees.

Other possible explanations

While these genetic differences could reveal a molecular biological mechanism that explains the bat’s enviable ability to stave off infections and cancer, researchers have proposed other ways the bat might have developed these virus and cancer fighting assets.

When a bat flies, it raises its body temperature. Viruses likely prefer a normal body temperature to operate optimally. 

Bats are “getting fevers without getting infections,” Scheben said.

Additionally, flight increases the creation of reactive oxygen species, which the bat needs to control on an ongoing basis.

At the same time, bats produce fewer inflammatory cytokines, which helps prevent them from having a runaway immune reaction. Some researchers have hypothesized that bats clear reactive oxygen species more effectively than humans.

A ‘eureka’ moment

The process of puzzling together all the pieces of DNA into individual chromosomes took considerable time and effort.

A Mesoamerican mustached bat, one of two bat species Scheben studied as a part of his comparative genomic work. Photo by Brock & Sherri Fenton

Scheben spent over 280,000 CPU hours chewing through thousands of genes in dozens of species on the CSHL supercomputer called Elzar, named for the chef from the cartoon “Futurama.” Such an effort would have taken eight years on a modern day personal computer.

During this effort, Scheben saw this “stark effect,” he said. “We had known that bats had lost some interferon alpha. What astounded me was that some bats had lost all alpha” while they had also raised interferon omega. That was the moment when he realized he found something novel and bat specific.

Scheben recognized that this finding could be one of many that lead to a better understanding of the processes that lead to cancer.

“We know that it’s unlikely that a single set of genes or a small set of genes such as we identified can fully explain the diversity of outcomes when it comes to a complex disease like cancer,” said Scheben.

A long journey

A resident of Northport, Scheben grew up in Frankfurt, Germany. He moved to London for several years, which explains his use of words like “chuffed” to describe the excitement he felt when he received a postdoctoral research offer at Cold Spring Harbor Laboratory.

When he was young, Scheben was interested in science despite the fact that classes were challenging for him.

“I was pretty poor in math and biology, but I liked doing it,” he said.

Outside of work, Scheben enjoys baking dense, whole wheat German-style bread, which he consumes with cheese or with apple, pear and nuts, and also hiking.

As for his work, which includes collaborating with CSHL Professor Rob Martienssen to study the genomes of plants like maize that make them resilient amid challenging environmental conditions, Scheben suggested it was the “best time to be alive and be a biologist” because of the combination of new data and the computational ability to study and analyze it.

Scheben recognized that graduate students in the future may scoff at this study, as they might be able to compare a wider range of mammalian genomes in a shorter amount of time.

Such a study could include mammals like naked mole rats, whales and elephants, which also have low cancer incidence and long lifespans.

Michael Schatz. Photo courtesy of Cold Spring Harbor Laboratory

By Daniel Dunaief

What if an enormous collection of Scrabble letters were spread out across the floor? What if several letters came together to form the word “victory”? Would that mean something? On its own, the word might be encouraging, depending on the context.

Genetic researchers are constantly looking at letters for the nucleotides adenine, guanine, cytosine and tyrosine, searching for combinations that might lead to health problems or, eventually, diseases like cancer.

For many of these diseases, seeing the equivalent of words like “cancer,” “victory” and “predisposition” are helpful, but they are missing a key element: context.

W. Richard McCombie

Michael Schatz, an adjunct associate professor at Cold Spring Harbor Laboratory who is also the Bloomberg distinguished associate professor at Johns Hopkins, and W. Richard McCombie, a professor at Cold Spring Harbor Laboratory, use long-read sequencing technology developed by Pacific Biosciences to find genetic variants that short-read sequencing missed.

The two scientists recently teamed up to publish their work on the cover of the August issue of the journal Genome Research. They provided a highly detailed map of the structural variations in the genes of a breast cancer cell.

“This is one of many covers [of scientific journals] that we are pleased and proud of,” said Jonas Korlach, the chief scientific officer at Menlo Park, California-based Pacific Biosciences. 

“This is another example of how long-read sequencing can give you a more complete picture of the genome and allow researchers to get a more complete understanding of the underlying biology and here, specifically, that underlies the transition from a health to a cancer disease state,” he said.

Schatz and McCombie were able to see fine detail and the context for those specific sequences. They were able to see about 20,000 structural variations in the cancer genome. “It’s like using Google maps,” explained Schatz in a recent interview. “You can see the overall picture of the country and then you can see roads and zoom out.”

In the context of their genetics work, this means they could see large and small changes in the genome. Only about a quarter of the variants they found could be detected without long-read technology.

In breast cancer, scientists currently know about a family of genes that could be involved in the disease. At this point, however, they may be unaware of other variants that are in those genes. Schatz is hoping to develop more sensitive diagnostics to identify more women at risk.

People like actress and advocate Angelina Jolie have used their genetic screens to make informed decisions about their health care even before signs of any problems arise. Jolie had a double mastectomy after she learned she had the mutation in the BRCA1 gene that put her at an 87 percent risk of developing breast cancer.

By studying the sequence of genes involved in breast cancer, researchers may be able to identify other people that are “at high risk based on their genetics,” Schatz said.

Knowing what’s in your genome can help people decide on potentially prophylactic treatments. 

When people discover that they have breast cancer, they typically choose a specific type of treatment, depending on the subtype of cancer.

“There’s a lot of interest to divide [the genetic subtypes] down into even finer detail,” said Schatz, adding, “There’s also interest in transferring those categories into other types of cancer, to give [patients] better treatments if and when the disease occurs.”

The reduced cost of sequencing has made these kinds of studies more feasible. In 2012, this study of the breast cancer genome would have cost about $100,000. To do this kind of research today costs closer to $10,000 and there’s even newer sequencing technology that promises to be even less expensive, he said.

Pacific Biosciences continues to see a reduction in the cost of its technology. The company plans to introduce a new chip next year that has an eightfold higher capacity, Korlach said.

Schatz said the long-term goal is to apply this technique to thousands of patients, which could help detect and understand genetic patterns. He and McCombie are following up on this research by looking at patients at Northwell Health.

In this work, Schatz’s group wrote software that helped decipher the code and the context for the genetic sequence.

“The instrument doesn’t know anything about genes or cancer,” he said. “It produces raw data. We write software that can take those sequences and compare them to the genome and look for patterns to evaluate what this raw data tells us.”

Schatz described McCombie, with whom he speaks every day or so, as his “perfect complement.” He suggested that McCombie was one of the world’s leaders on the experimental side, adding, “There’s a lot of artwork that goes into running the instruments. My lab doesn’t have that, but his lab does.”

Working with his team at CSHL and Johns Hopkins has presented Schatz with numerous opportunities for growth and advancement.

“Cold Spring Harbor is an internationally recognized institute for basic science, while Johns Hopkins is also an internationally recognized research hospital and university,” he explained. He’s living in the “best of both worlds,” which allows him to “tap into amazing people and resources and capacities.”

Korlach has known Schatz for at least a decade. He said he’s been “really impressed with his approach,” and that Schatz is “highly regarded by his peers and in the community.”

Schatz is also a “terrific mentor” who has helped guide the development of the careers of several of his former students, Korlach said.

Down the road, Schatz also hopes to explore the genetic signature that might lead to specific changes in a cancer, transforming it from an organ-specific disease into a metastatic condition.