Work bridges sciences and liberal arts

The interview had barely begun when a link was established. “I’m U4,” she confided. “I’m U2,” he replied, adding “we share a really close direct maternal ancestor.”

It’s everyday conversation for Brian M. Kemp, a molecular anthropologist who studies the genetics and migration patterns of prehistoric peoples — whose lineages typically are designated by letters and numbers.

Kemp, assistant professor in both the School of Biological Sciences and the Department of Anthropology, is one of a scant dozen researchers in the nation who specializes in the new field of ancient DNA, primarily focusing on the heritage of Native Americans.

He is also the first, in the past 30 years, to have a cross-college appointment between the College of Sciences and the College of Liberal Arts, according to Michael Griswold, CS dean.

 

Time capsules
Ancient DNA (aDNA) refers to genetic material extracted directly from archeological specimens. Modern DNA, taken from living people, may give suggestions about the past based on genetic theory, but only ancient DNA can directly test these hypotheses.

Archeologists who once had to speculate about the biology of past peoples can now use molecular analysis to confirm sex, address kinship patterns and population relationships, document human migration routes, reconstruct prehistoric diets and study human behavior and disease.

“With aDNA, time is no longer an issue … we skirt around time,” said Kemp. Today archeologists can find a point in the past and compare it to a point in contemporary populations — and are able to say that someone’s maternal ancestor was present in a certain cave, for example.

As it turns out, some of the best sources of aDNA are coprolites, quids and aprons preserved in caves in the desert Southwest.
Coprolites are samples of desiccated prehistoric feces. Quids are like ancient cheek swabs.

“People used to chew up yucca and spit it out,” Kemp said. “We don’t know why they did it, but a lot of them did it.” Kemp and colleagues recently documented, for the first time, that roughly 30 percent of quids contain useable aDNA.

“Aprons” — or woven menstrual belts — can also supply aDNA. Kemp has obtained samples from the Brooklyn Museum of Art, but reports there are hundreds of aprons piled up in caves available for sampling.

 

Native American ancestry
Why not just sample prehistoric bones or other tissue directly? Kemp says that while he has successfully studied bones, some people do not appreciate archeologists digging up their ancestors. Also, the process of obtaining samples is destructive — having to cut into bones or teeth. Coprolites, quids and aprons offer a non-invasive method of documenting the past.

Using coprolites, Kemp has been able to trace the migration of a rare branch of Native American people (haplogroup C) from Owen’s Valley in California between 700 to 2,000 years ago to today’s Paiute and Washoe tribes in the Great Basin.

Another exciting finding came from 10,300-year-old aDNA extracted from a skeleton in On Your Knees Cave on Prince of Wales Island in Alaska. Kemp and his colleagues determined that the individual belonged to a previously unknown line — haplogroup D4H3 — that had migrated from Asia to America and subsequently all along the west coast of North and South America.

“What we found was shocking,” he said. “Only about 1.4 percent of Native Americans have this type (of DNA).”

Though he says his area of expertise is “kind of a novelty at this point,” Kemp’s goal while at WSU is to open the door to large population studies — something that has never been done before.

“I plan to look at genetic variation in the Southwest over a 6,000-year period,” he said. “Using hundreds of samples … we want to get a big overview picture of the population — and be able to watch them move and live and eat.”

For more on Kemp and his work, see ONLINE @ www.libarts.wsu.edu/anthro/faculty/kemp.html.

 

Who’s your mommy?  
U2 and U4 are just two of many designations for specific lines of maternal mitochondrial DNA (mtDNA) with migration paths that have been traced throughout the world. For around $100 and a painless cheek scraping, you can have your DNA traced.

 

For information on tracking your family heritage see ONLINE @ www.3.nationalgeographic.com/genographic or www.familytreedna.com.

 

Breakthrough named to ‘Top 100’ list
Kemp’s research is one of two ground-breaking studies by WSU teams that are among the top 100 science stories of the year, according to Discover magazine.

Kemp’s work produced the oldest sample of human genetic material from the American continents ever examined. Working with colleagues, Kemp extracted DNA from a 10,300 year-old human tooth.

Their findings, published last January in the American Journal of Physical Anthropology, support the hypothesis that humans arrived in North America later than previously thought and then migrated south along the Pacific coast.

The researchers compared the ancient tooth’s DNA with modern DNA to calculate when the first Americans landed on the coast of Alaska. Using a “molecular clock” of mutation rates, Kemp estimated the first arrivals happened within the last 15,000 years. Previous estimates had set the date as far back as 40,000 years.

The second team, led by molecular biologist Michael Skinner, made the list for the second time in three years. He collaborated on a study showing that one-time exposure to an environmental toxin can affect the breeding behavior of the exposed animal’s descendants.

The study built on the WSU team’s previous “top science story,” their 2005 discovery that in utero exposure to a commonly-used fungicide produces cancers and other health problems in the exposed rat’s male descendants, through several generations.

The 2007 list of top science stories was announced in Discover magazine’s January issue, available in print and ONLINE @ http://discovermagazine.com/ to subscribers.

 

For addional information on DNA patterns, visit http://www.spokesmanreview.com/local/story.asp?ID=227495.