To see to the core of the human biology and behavior, one effective method is to study our closest living relatives. That approach represents the philosophy behind the Duke University Primate Center's research efforts and an increasing number of scientists developing their research there.
The Primate Center houses the largest collection of endangered primates in the world, including the largest collection of prosimians--humans' furthest-removed primate cousins. It gives researchers the rare opportunity to work with prosimians in a natural setting and gives humans in general a wider perspective on our place in nature.
"The Primate Center gives us a chance to look at parallel evolution between humans and prosimians," said William Hylander, director of the center and professor of biology and biological anthropology and anatomy. "We can view prosimians as a starting point for the evolution of higher primates and an endpoint for what the earliest primates looked like."
Researchers from all over the world apply every year to come to the center, sometimes just for the summer, to test their research hypotheses, Hylander said. The Primate Center is especially important because in many cases it houses the only members of a particular species in captivity in the entire world. Since July 2001, at least 42 new research protocols have become active at the center, he said.
The new protocols are helping the center satisfy one of the University's main priorities for it; last year, the administration replaced the center's director and raised the possibility of closing the center if it did not increase its research.
Ongoing research at the Primate Center includes studies of locomotion and chewing, hormones and behavior, digestion, anatomy, the evolution of color vision, olfaction and learning-all fields that provide major insight into the behaviors and evolutionary patterns of early humans.
"The Primate Center provides me with another way to develop questions derived from field research," said Diane Brockman, assistant research professor of biological anthropology and anatomy.
Brockman's research is typical of the kind of projects that are occurring at the center. When she came to Duke in 1995, she had been interested in pursuing issues involving reproductive competition in Verreaux's sifaka, a species of prosimian, and had done most of her research in Madagascar, the home of most of the world's prosimians.
After studying the Coquerel's sifaka, a subspecies of Verreaux's sifaka, at the Primate Center and finding out that adult females reproductively suppress their daughters, Brockman expanded her research efforts to try to determine whether Coquerel's sifaka is the only subspecies of sifaka that exhibits this type of behavior. Since the Primate Center houses a diversity of species, researchers can test the behavior of one species or subspecies against the behavior of another.
Another type of research that Brockman is now considering is the study of the DHEAS hormone, which is a biomarker of aging in many mammals including humans.
"In humans the levels of DHEAS decrease with age, while in sifaka there are no age-related changes," said Brockman. Research has shown that in humans, DHEAS levels are also depressed in a number of disease states including lupus, AIDS, cancer, diabetes and cardiovascular disease.
Studies with DHEAS in sifaka may have health-related implications for humans. If DHEAS is similar in humans and sifaka, Brockman is considering researching what aspect of hormonal regulation has changed during primate evolution to give us the human pattern.
Researchers are also considering studying aging in primates.
"Prosimians present us with some good primate models for aging because certain species express cognitive deficits as they age," Hylander said, citing Alzheimer's disease as an instance where research on prosimians might provide such models.
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