Posted on April 19: A tale of two relics
[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/Hendrik_Poinar_opt.jpg” caption=”Hendrik Poinar_opt”]Hendrik Poinar, assistant professor in anthropology, holds two prehistoric fossils. One, long and slender, is a 30,000-year-old cave bear tooth. It holds valuable information that gives important clues about when bears migrated from Europe, how diverse they were prior to their extinction and how they're related to polar bears, black bears, and brown bears, as we know them today.
The other fossil, a small round lump with holes throughout, is much more interesting to Poinar. It provides valuable anthropological information, offering clues to where humans lived, how diverse they were, what they ate, and their interrelatedness. It's a piece of human feces, 9,000 years old, from Southwest Texas.
“People often think the bear tooth is so much more interesting because it's a piece of this huge creature they can only imagine,” says Poinar, holding it up to his mouth to demonstrate the grandeur of the prehistoric beast. “But in this single remnant of human feces we were able to learn so much more about human diet, disease, migrations, and the local environment and climate at the time of the peoples.”
That's the miracle of the chemical and molecular analysis that allows Poinar and his research team which includes his wife, research associate Debi Poinar to work with ancient molecular information to answer anthropological or evolutionary questions. Their analysis is giving them answers about the kind of life the first American people lived, the evolutionary differences between animals such as the giant extinct grount sloth with the living two-toed and three-toed sloth, and how SIV found its way from African chimpanzees to HIV now prevalent in more than 40 million humans.
“We work on uncovering the chemistry of fossils to understand how to tease the interesting biomolecular information out, and we use this information to address questions on the evolution of extinct hominids, the reasons the megafauna (mammoths, horses, camels, sloths) went extinct 11,000 years ago and when and how HIV originated and continues to evolve” says Poinar. “Modern biology is in essence time-trapped, because scientists are required to use current samples to make assumptions about the past, but I work with how that organism was in the past using fossilized samples.”
Poinar developed an appreciation for that sense of “time travel” by going on digs with his father, prominent American entomologist George Poinar, at an early age.
“As a kid I was fascinated with palaeontology, but I became more interested in molecular biology,” says Poinar. “In working with ancient DNA I've been able to mesh the two.”
Using fossilized feces from Southwestern Texas he determined the samples were from indigenous Amerindians. The molecular information contained in the fossils help him understand the environment in which they lived, which was distinctly different from the barren desert the cave exists in today.
The fossils revealed that the environment was green and lush, with an abundance of edible plants and animals. Within a two-day period (the time-frame the researchers allowed for consumption and digestion of the food found in the feces,) these hunter-getherers had consumed up to five animal types including antelope, big horn sheep, and rabbit, as well as 12 types of plants.
“Who would have thought hunter-gatherers were so well-fed?” says Poinar. “We often think of these populations as poor, malnourished tribes scrounging for berries, but in reality they were eating better and more balanced meals than many of us today.”
What they ate, where they lived, how far they moved for resettlement, and the extent of their gene pool are just some of the characteristics Poinar was able to discover through millennia-old biological matter.
Now, he's looking for similar clues in early samples of HIV, to learn more about the origins and tempo and mode of HIV evolution, from the area formerly known as the Belgian Congo.
“Medical records from the early 1960s show that Belgian doctors were noticing symptoms of a strange immune-suppressing condition among people in the Belgian Congo,” says Poinar. “We want to know what that disease looked like in the 1960s so we can learn how it evolved.”
Poinar and his wife, have collected some of the oldest samples of archival HIV that doctors and researchers had taken from patients who have since succumbed to the disease. The samples range in dates from 1959 to the late 1970s, and Poinar believes they'll tell him where the epidemic began, and how it has since evolved. He also hopes the samples may clue him and others on to the possibility of using ancestral strains for future vaccine development.
He's combining that study with a large-scale project that looks for the level of infections in chimpanzees, using freshly collected feces in the present-day Congo. The researchers scan the feces for a number of details, including parasites and the presence of SIV. This will enable Poinar to determine, from which source population of chimps the original SIV spread to humans, leading to HIV.
“What we do has a lot to do with health, biochemistry, geography and anthropology, and I really value the ability to work across disciplines,” says Poinar. “I try to surround myself with people who think broadly and ask the big questions, but who work meticulously.”
Poinar's research team also includes research assistants Melanie Kuch, and Carsten Schwarz from Germany, postdoctoral fellow Robert Blatter from Switzerland, and graduate students Jodi Barta and Tanya von Hunius from Canada.
Photo caption: Hendrik Poinar, assistant professor in anthropology, holds a 9,000-year-old human feces fossil in his right hand and a 30,000-year-old cave bear tooth in his left. Poinar works with ancient molecular information to answer anthropological or evolutionary questions. Photo credit: Chantall Van Raay
