Linking the Past

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Kennesaw State professor’s Arctic research offers hope in the study of birth defects…

Georgia (Nov 15, 2011)

Kennesaw State professor’s Arctic research offers hope in the study of birth defects

Evolutionary biologist Marcus C. Davis delves into the past with an eye on the future, knowing that his research will shed new light on birth defects and limb regeneration in humans.

An assistant professor of biology in KSU’s College of Science and Mathematics, Davis spends summers digging for fossils in the Canadian Arctic where temperatures hover around freezing and the sun never sets.

Davis was among a group of researchers led by the University of Chicago’s Neil Shubin, that made a key discovery while exploring 375 million-year-old fossilized streambeds 600 miles from the North Pole ╤the skeletons of well-preserved fossil fish.

They were searching for what Davis describes as a transitional organism between fish and land-living vertebrates, which possessed attributes of both fish and amphibians.

 “What we found was a mosaic animal with long and muscular limbs like an amphibian, with a fish-like fin at the end for swimming,” he said. “Unlike fish, it had a distinctive neck ╤a key attribute that allows land animals to move their head independently from their body.”

The team named the “missing link” fossil Tiktaalik(pronounced tic-TAH’-lic) roseae, and nicknamed it the “fishapod,” or fish with feet.

The New York Times quoted H. Richard Lane, director of paleobiology at the National Science Foundation, as saying, “These exciting discoveries are providing fossil Rosetta Stones for a deeper understanding of this evolutionary milestone ╤the link from fish to land-roaming tetrapods.”

Davis said his current research explores the mechanisms of evolutionary change that underlie the origins of new animal body plans. “I integrate information from the fossil record with the investigation of developmental mechanisms in living vertebrates. I’m trying to determine whether fish have fingers, or something that became fingers in all of us ‘land fish.’”

The patterns of limb evolution across hundreds of millions of years have allowed researchers like Davis to develop hypotheses about how limbs form and which genes are involved.

So, besides the evolutionary insights, these discoveries may lead to medical breakthroughs since many fish and amphibians can replace damaged or lost limbs.

Since these vertebrates and mammals, including humans, use mostly the same genes to build their limbs, researchers are confident it will one day be possible to regenerate lost digits and limbs in humans.

“Insights from our study also have allowed us to clarify the very confusing observations that have been made regarding birth defects in humans. Which is why, in polydactylism, one of the most common forms of birth defects, there are extra digits ╨six, seven or eight but never more than eight digits,” Davis said.

Davis made a return trip to the Arctic this summer. “It is now time to open the next chapter in exploration and I have been invited back to play a role,” he said. “We are excited to explore some new exposures, on new islands, that we did not explore over the last decade.”

 

-- Robert Godlewski


 

A leader in innovative teaching and learning, Kennesaw State University offers more than 150 undergraduate, graduate and doctoral degrees to its approximately 41,000 students. With 11 colleges on two metro Atlanta campuses, Kennesaw State is a member of the University System of Georgia and the third-largest university in the state. The university’s vibrant campus culture, diverse population, strong global ties and entrepreneurial spirit draw students from throughout the region and from 92 countries across the globe. Kennesaw State is a Carnegie-designated doctoral research institution (R2), placing it among an elite group of only 6 percent of U.S. colleges and universities with an R1 or R2 status, and one of the 50 largest public institutions in the country. For more information, visit kennesaw.edu

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