As an example, her recent study of teeth in more than 400 savanna baboons housed at the Southwest Foundation in San Antonio shows that, contrary to long-held assumptions, enamel thickness varies widely within a population. She and her colleagues also found that the underlying genetic architecture may have enabled rapid evolutionary changes in enamel thicknesses that could reflect changes in dietary habits over time.
The study, published online ahead of print by the American Journal of Physical Anthropology, is the largest genetic analysis of primate enamel thickness done so far.
"People have assumed that it is hard to change certain traits -- that if an organism has evolved thick enamel, its descendents cannot easily go back to thin enamel," she said. "The thinking has been that if hominid fossils 5 million years old have thick enamel, they are human ancestors. If they have thinner enamel, they must be chimpanzees."
That assumption, Hlusko said, "may be over simplified." Using their baboon study, Hlusko and colleagues argue that "when used uncritically, enamel thickness has the potential to confound rather than to clarify phylogenetic studies of higher primates."
The Monday morning AAAS session reflects a desire to "see integrative paleontological and genetic approaches as the norm rather than the exception in primate and human evolutionary studies," Hlusko said at a news briefing on Sunday. This integrative approach was first developed by scientists working outside the study of primates, such as Rudolf Raff of Indiana University, also a participant in the AAAS symposium. One of the goals for the symposium and Hlusko's PNAS article is to highlight the application of integrative biology to hum
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Contact: Jim Barlow, Life Sciences Editor
jebarlow@staff.uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
15-Feb-2004