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“The key event that led to our change in perspective about human evolution is the shocking surprise that humans are animals. That's a revolution that continues to the present day and has still not been completely digested by society at large, by artists, and even by scientists. ”

-Chris Beard, Curator and Head
Section of Vertebrate Paleontology
Carnegie Museum of Natural History

 

 

 

 

 

 

 

 

“There are now six different species of mammals—human, mouse, rat, dog, chimpanzee and cow—whose genomic maps have been completed….The fundamental concept is that we are tied together with one genealogy. We have one family tree. ”

-Zhe-Xi Luo, Associate Director of Research and Collections
Carnegie Museum of Natural History

 

 

 

 

 

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Evolutionary Medicine

Carnegie Museum of Natural History scientists will soon be teaching Pitt medical students lessons in where they came from—and why, when treating and diagnosing disease, evolution matters.

Among those looking forward to the unveiling of Fierce Friends, Carnegie Museum of Art’s examination of the changing depictions of animals in 18th- and 19th-century art (see page 16), are the scientists of Carnegie Museum of Natural History next door, who dig the deepest roots of the human family tree. The exhibition provocatively conveys how man’s increased understanding of the natural world informed the artists of the time. And it hints at how Darwin’s theories about our animal ancestry—introduced in the late 19th century—would totally rearrange the natural history of humankind and, years later, would still roil the culture.

“ The key event that led to our change in perspective about human evolution is the shocking surprise that humans are animals,” says Chris Beard, head of the museum’s Section of Vertebrate Paleontology. “That's a revolution that continues to the present day and has still not been completely digested by society at large, by artists, and even by scientists.”
Contemporary medical issues, from the origins and transmission of disease to an aching back, have roots that go back millions of years in human and animal development—an astonishing connection for those who associate evolution with the cave man, and medicine with penicillin. And soon, Museum of Natural History scientists will be illuminating that connection in a course created for University of Pittsburgh medical students on the natural history of medicine.

“ I have long wanted to teach our medical students that diseases and disorders can only be fully understood in a social, cultural, and historical context,” says Arthur S. Levine, M.D., senior vice-chancellor for the health sciences and dean of the medical school. “Without such a robust context, physicians and medical researchers may miss critical connections that help us to understand the origins of human illness and how this knowledge may lead to new ideas for prevention and treatment.

“ The museum’s new course is our next step in integrating contemporary medicine with the whole history of biology,” Levine adds. “Moreover, it weds two of the country’s most outstanding institutions—the medical school and the Museum of Natural History—in a relationship that promises new and rich opportunities for scientific as well as educational collaboration.”

Bill DeWalt, director of Carnegie Museum of Natural History, marvels at the collective brainpower the course will feature on both sides of the lectern: “It’s exciting to both institutions to be collaborating at this level,” DeWalt says. “Our scientists are internationally renowned for their work delving into the evolution of life in all its forms. And they’ll be sharing their knowledge with the best and brightest future physicians and researchers in this country. Only great things could come of that.”

Old-Fashioned Biology
The decision to broaden the Pitt curriculum stems from parallel research questions in natural history and medicine.

Beard explains: “We live today at a sort of great harmonic convergence of biology—where old-fashioned biology, like what we do at the museum, is suddenly becoming more relevant to modern biology. We’re starting to put together genetic aspects of evolution with what we know about the fossil record and anatomical change through time. And physicians are becoming more aware that medicine itself is evolutionary; that disease-causing microbes are constantly evolving.

“ Natural Selection is the only explanation for why certain strains of bacteria become immune to antibiotics,” says Beard—a point, he notes that shouldn’t be lost as we grapple with some vexing health issues. “People are worried about whether bird flu virus is going to mutate. So, an evolutionary perspective, which is usually absent from most medical school curricula, needs to be re-inserted. It’s critical.”

John Lazo, M.D., the Allegheny Foundation Professor of Pharmacology and Director of the Drug Discovery Institute (and a Museum of Natural History board member), agrees. “These scientists have a vehicle that allows us to ask questions about biology that are unique in terms of medical schools,” he says. “We typically use just a few species, like mice and zebrafish, to ask profound questions about diseases and ways to treat them. But they have hundreds of thousands of species—some of the finest collections in the world.”

John Wible, curator of mammals for the museum, sees the museum’s holdings as a valuable medical resource: “We have a very broad-based collection of recent mammals that can be useful in teaching topics relevant to medicine, such as the evolution of the brain.”

Physician, Know Thyself
It’s not only their specimens that Carnegie Museum scientists will offer to Pitt’s 600 doctors in training, but their broad scientific perspective, too. Their course, entitled the Natural History of Medicine, will be presented as an elective beginning this year. (Medical students are also required to complete a multi-year mentored scholarly project and may choose a topic related to the museum’s strengths.)

The course instructors are some of the museum’s most eminent researchers. Chris Beard and his colleague Zhe-Xi Luo, the museum’s associate director of science and collections, will join John Wible and Sandra Olsen, curator of anthropology, as instructors. Beard’s research focuses on the evolution of primates; Luo, who currently teaches a course on evolution at the University of Pittsburgh, has co-authored groundbreaking research on early mammals with Wible; and Olsen has explored 5,500-year-old pastoral cultures (see Face Time).

The scientists say that enriching medical students’ understanding of natural history isn’t merely esoteric: it will make them better doctors, allowing them to better explain medical conditions to patients and determine treatments.

“ When our ancestors decided to rise up on their hind legs and start walking around like us, instead of on all fours, that was a good thing because it allowed us to do things with our hands,” Beard explains. “But at the same time, it made it hard for women to give birth. And it also leads to chronic lower back pain, hernias, and all kinds of orthopedic problems with knees and ankles.”

And athletes, take note: “Our arms have evolved the capacity for enormous mobility at the shoulder joint from (yes) hanging from branches,” Beard explains. “That allows modern humans to pitch baseball, which is something the average mammal, such as dogs and cats, can’t do. As quadrapeds, their shoulder joints are built for stability, even if that means they lack the full range of motion that we have. The price we pay for our wide range of shoulder mobility is a big decrease in joint stability, which makes us prone to injury, especially rotator cuff injuries. By making students aware of the evolutionary history behind these things, hopefully we’ll make them better doctors—more engaged and more curious.”

Lazo puts it in clinical context: “Anatomy can be dry. You can memorize, or you can make the connection. Take the eye: you can describe it, or you can show how it evolved. Discussing why nocturnal animals can see better, then looking at cones and rods in their eyes, you can compare animal to human. Then you can
discuss macular degeneration [deterioration of the retina] and really understand the process.”

Prehistoric Diseases and Early Cures
When Lazo, who co-directs the molecular therapeutics/drug discovery program at the University of Pittsburgh Cancer Institute, presents his latest research findings, he typically includes a favorite slide given to him by the Museum of Natural History’s paleontologists: a photograph of 150-million-year-old cancerous tumor from a Jurassic dinosaur. “It’s always my second slide—a free ad for the museum,” he jokes. “But it makes the point. When you see a 150-million-year-old tumor, you realize cancer has been around for a long time. It’s not just because we smoke.”

Carnegie Museum scientists can recognize several contemporary diseases in fossils that predate human existence. Zhe-Xi Luo recalls one of the museum’s meat-eating dinosaurs, or therapods, whose skeleton showed evidence of gout. (“They drank port, too!” jokes Wible.)

The bones of certain living creatures with prehistoric roots might even give modern researchers clues for fighting cancer, Olsen suggests. “They’ve never been able to induce or diagnose cancer in sharks,” she notes. “So, although in some ways they are more primitive, their cartilage is thought to suppress the development of the arterial system of tumors.” Finding that mechanism, she says, may yield data for human treatment.

And just as the evolutionary record shows the longevity of disease, Olsen says it may also suggest natural remedies: “Look at the thousands of years people have been using herbal medicines and natural products to great advantage. Many of these are far less destructive to the human cell than chemotherapy or radiation. A lot more can be learned about prevention by utilizing that knowledge.”

Lazo agrees, noting that pharmacology has barely scratched the natural surface. “More than 50 percent of drugs come from natural products,” Lazo says. “The best estimate is that we have looked in one percent of nature for drugs—[not] the other 99 percent of species. We know there are millions of possibilities, but we have not systematically evaluated them. That’s what these folks do. They’re interested in organizing how species are related.” (A Pitt team is currently scanning 75,000 natural extracts from the National Cancer Institute, and Lazo reports that they have found several with potential anti-cancer properties.)

The Evolution of Disease
The natural sciences also have much to teach us about disease-causing pathogens, which often evolve even faster than we do. Viruses quickly figure out how to outsmart antibiotics by mutating. The same defensive ability allows them to jump from one species to another. The 1918 flu pandemic, which killed nearly 40 million people, began as a virus native to wild birds—just like the avian flu that worries epidemiologists today.

“ Why is it that SARS and all kinds of ugly influenzas are always coming from
Asia to North America, and never vice versa?” Beard asks. “Because Asia is a hotbed for biological diversity. And it also happens to be a place where lots of people are interacting with lots of different life forms on a very personal level, so its flu viruses are more diverse and more potentially virulent.”

Olsen has seen parallels in early Asian cultures. “When people start domesticating animals, they are much more intimate with animals than ever before,” Olsen explains. “Certain diseases can be easily transmitted through direct contact with animals or their byproducts; and others can be transmitted through wild animals, by exposure or ingestion.” She uses as an example the practice of certain African cultures eating chimpanzees, which are subject to deadly forms of diseases that also affect humans. “That really sets the stage for transmission.”

Even when it doesn’t involve disease, diet affects the health of cultures. Olsen offers another Asian analogy: “Among Mongolian pastoralists, who depend heavily on dairy products, it’s rare to find lactose intolerance. In China, where people historically rarely consumed raw milk, it’s the norm.”

One Big Family
Recent headlines on genetic findings have linked three million Irishmen worldwide with one common ancestor, and most Ashkanazi Jewish women trace just four matriarchs.

Meanwhile, comparing the complete human genome to animals is allowing researchers to see more clearly how our species is related to others, says Luo.

“ There are now six different species of mammals—human, mouse, rat, dog, chimpanzee, and cow—whose genomic maps have been completed,” Luo explains. “When you see one expression of a gene in rodents, and you have another similar correlating one in humans, you know these genes are tied to the same kind of function. But think about the larger picture: compare a rodent with a chimpanzee and a human being. The fundamental concept is, we are tied together with one gene-alogy. We have one family tree.”

Beard adds that environmental health and global health, research areas in which the University of Pittsburgh has an international reputation, also can be enhanced by the museum curators’ expertise in archaeological populations.“

Some global societies are still dealing with diseases like leprosy, tuberculosis, or untreated syphilis,” Beard says. “Sandi, in particular, will bring expertise to bear on the health of past populations.”

“We can, and should, look at working conditions and environmental conditions in prehistoric times,” Olsen says. “Archaeologists employ the same techniques as forensic scientists to determine how humans died. That’s how we knew that one of the Bog People, a 16-year-old girl (from a recent museum exhibition on the remains of ancient Europeans), had severe scoliosis and walked with a limp. We also know that Romans had pipes made of lead, a source of lead poisoning. You can even tell from a skeleton if someone habitually rode a horse.”

John Mahoney, M.D., assistant dean for medical education at Pitt medical school, is excited about all that the new collaboration will mean to the students and researchers. “It can broaden student horizons by showing them how medicine is a piece of the broad domain of natural sciences, and how understanding the natural sciences will enhance learning about medicine,” Mahoney says. “And I think this shows that we have an academic community that plays well together.”

Just as Pitt researchers benefit from synergies with other Oakland neighbors, like Carnegie Mellon, Mahoney foresees that they’ll also benefit from the wealth of expertise offered by museum scientists. For their part, the museum’s scientific team is looking forward to working with Pitt’s cutting-edge equipment such as scanning electron microscopes. “They have much better facilities and the newest equipment for research, which they’ve offered to share with us on joint projects,” says Olsen.

Beard sees the ultimate product of the collaboration as being “reciprocal illumination.”

He adds: “Our knowledge and insight will illuminate biomedical issues, and the insight and expertise on the Pitt medical school side will help us address issues
we’re concerned with. That would be a perfect result.”

THE EVOLUTION SCIENTISTS:
Chris Beard

Position: Curator and Head, Section of Vertebrate Paleontology; joined staff in 1989

Education: Ph.D., Johns Hopkins University School of Medicine

Research Interests: Biogeography, primates, and the basis of evolution. “John and Luo are interested in heads. I’m interested in limb
anatomy—arms and legs.”

Career Highlights: MacArthur Fellow, 2000-2005; award-winning author, The Hunt for the Dawn Monkey: Unearthing the Origins of Monkeys, Apes and Humans, 2005
Sandra Olsen

Position: Curator of Anthropology; joined staff in 1991

Education: Ph.D., University of London

Research Interests: Early horse domestication in Central Asia,
c. 3500 B.C.; violence. “I use for-ensics to identify kinds of wounds.
I also look at wounds in animals, whether they were hunted with a stone projectile point or a bone
projectile point.”

Career Highlights: Nine field
expeditions to Kazahkstan since 1993, funded by National Science Foundation. Currently editing Horses and Humans: The Evolution of the Equine Human Relationship. Past research on skeletal remains of Northern Plains Indians has promoted a continuing study of anthropological violence
John Wible

Position: Curator and Head, Section of Mammals; joined staff in 1998

Education: Ph.D., Duke University

Research Interests: Skulls and teeth of early and living mammals. “We have a very broad-based
collection of all mammals. I have
an incredible collection that I can bring to any number of topics.”

Career Highlights: collaborative research (with Z.X. Luo and others) published in Science, Nature, and other peer-reviewed journals; senior editor of the museum’s scientific publication series
Zhe-Xi Luo

Position: Associate Director of Research and Collections; Curator, Section of Vertebrate Paleontology; joined staff in 1996

Education: Ph.D., University of California at Berkeley

Research Interests: Origins of early mammals, origins of mammalian skull growth (face and teeth). “All human beings have only two generations of teeth. It turns out the origin of this dental replacement pattern can be documented from fossils that are 220-190 million years old.”

Career Highlights: Recipient of National Science Foundation CAREER award; led the team of museum scientists that discovered a new 150-million-year-old species of early mammal, dubbed "Popeye" because of its massive forearms; adjunct faculty member at the University of Pittsburgh

 

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