Hendrik Poinar is holding a small plastic vial containing some of the oldest DNA ever extracted from human remains. The snips of genetic material are from a native American who made his home 8,000 years ago in a massive cliff-side rock shelter in southwestern Texas.
Dr. Poinar, an assistant professor in the department of anthropology, pathology and molecular medicine at McMaster University in Hamilton, believes that this ancient DNA holds the answers to a host of major scientific questions: Did the first peoples come to North America in a single migration, or several? What were the pre-Columbian diseases on this continent? Were there dietary differences between the sexes in archaic hunter-gatherer populations?
But what he is most excited about is the unusual source of this genetic information. It's not from old bones or teeth, but fossilized feces, or coprolites , which he believes will reveal more about ancient human and pre-human life than any other source of DNA.
"Coprolites are fantastic sources of DNA. It turns out that with bones and poop from the same cave, the poops outdo the bones in terms of DNA yields by up to 10-fold," he says.
Dr. Poinar's molecular coproscopy is doing more than providing an intriguing bottom-up view on the past. He is writing the latest chapter in a surprising Canadian saga that began with a McGill University scientist whose pioneering coprolite work in the 1950s and 60s was initially dismissed.
Now, the power of old poop to tell amazing human stories is being heralded by Dr. Poinar and others in the world's leading scientific journals.
Just six months into Dr. Poinar's current job -- he chose McMaster over offers from Oxford and the University of California at Berkeley -- his four-member research group is meticulously constructing a million-dollar lab. It will soon be among the world's most sophisticated for teasing a string of A, T, C and G base pairs out of coprolites and other sources of ancient DNA, a field known as molecular anthropology.
Dr. Poinar comes naturally to the search for ancient DNA. His father is the "insects-in-amber guy," George Poinar, the Berkeley paleontologist and entomologist whose work is the basis for Michael Crichton's vision of genetically reconstituted dinosaurs, Jurassic Park.
But even with this pedigree, Hendrik Poinar fell into the study of coprolites. Working on his PhD in the mid-1990s at one of the world's leading ancient DNA labs at the University of Munich, he was intrigued by the desiccated doo-doo stored in the basement with the more respectable archeological and paleontological artifacts. The puffball-shaped ice age coprolites were from Gypsum Cave, Nev., just south of Las Vegas.
Other researchers had found it impossible to extract DNA from these or any other coprolites, and written them off as just a lot of old dung.
"I found them fascinating because you radio-carbon-dated them and they were between 20 and 50 thousand years old and they looked just way too well preserved to have nothing preserved in them on the molecular scale," Dr. Poinar says.
Getting information from fossilized feces may seem like a long shot. After all, as anyone with a dog knows, droppings quickly erode with rain and snow.
However, in dry environments -- including caves, deserts and high-altitude areas -- feces are commonly preserved and found as part of archeological and paleontological digs.
(They are also found frozen in the Canadian North, says David Morrison, an archeologist at the Canadian Museum of Civilization, who has come across 400-year-old frozen sled-dog droppings.)
Dr. Poinar believed that the key to unlocking the DNA from coprolites lay in understanding their chemistry. So he spent six months with leading organic chemists at the University of Bristol molecularly dissecting his coprolites and found a rainbow of "fantastically preserved molecules," including proteins and sugars -- but no DNA.
The DNA denouement came from diabetes research. "The thing that diabetes and ancient shit have in common is that they produce condensation products because of excess sugar," Dr. Poinar says.
When sugars are heated, they lose water and form condensation products in what's called the Maillard reaction. It's this reaction that produces many of the mouth-watering aromatic smells associated with baking and frying foods.
In diabetics, these Maillard products stick to the arterial walls, causing hardening and resulting in cataracts and the gradual loss of circulation to the limbs. In 1996, a team of New York researchers reported on its discovery of a drug called PTB that cleaves the Maillard products from the cells of the arterial walls.
"That's when the light bulb went off in my head and I said, 'Why not stick this into your coprolite extractions and see what happens,' Dr. Poinar says.
Bingo. Not only was the DNA present, chemically trapped in a "molecular sandwich" by the Maillard products, it was also well preserved.
Using this technique, Dr. Poinar performed the world's first paleo-defecator identification. He DNA-printed the pooper of his paleo-dung as an extinct species of giant ground sloth, whose bones were also found in Gypsum Cave.
Next, Dr. Poinar turned to the most intriguing field of ancient DNA, human remains. He analyzed several 2,000-year-old coprolites from Hinds Cave in southwest Texas.
"It's one of the biggest crap deposits known," says Vaughn Bryant, an anthropologist at Texas A&M University who led the excavation of the Hinds Cave deposit in the mid-1970s and provided Dr. Poinar with the samples.
The cave, an enormous, very dry, cliff-face rock shelter, housed generations of hunter-gatherers for 9,000 years. The site has yielded more than 2,000 cow-patty-shaped human coprolites.
The shape of these coprolites is due to the "astronomical" amounts of fibre in them, Dr. Bryant says. He estimates that the Hinds Cave inhabitants ate 15 times the daily fibre intake of present-day North Americans, mostly in the form of roasted desert plants, including agave and yucca.
Using mitochondrial DNA analysis, Dr. Poinar showed that three coprolites belonged to separate individuals. And he confirmed Dr. Bryant's microscopic analysis of the contents: These paleo-peoples were eating well.
Through genetic reconstruction, he showed that in the 24 to 48 hours before relieving himself at the back of the shelter, one Hinds Cave resident had eaten a veritable Thanksgiving feast. The coprolite included evidence of pronghorn antelope, cottontail rabbit, packrat, squirrel and eight types of wild plants.
"A bone now is completely boring to me," Dr. Poinar says. "Because the bone gives the DNA of the organism itself, but the coprolite gives the DNA of the organism, what it ate, of any parasites he may have harboured. I mean it's a plethora of information."
Coprolite DNA analysis has its detractors, even from within the coprolite community.
"I still think it's kind of hocus-pocus stuff myself," says Dr. Bryant, who wonders about the possibility of genetic misidentification based on fragmentary pieces of DNA, and leans more toward his own specialty of pollen analysis from coprolites.
Nonetheless, he has lent Dr. Poinar 300 Hinds Cave coprolites, one of which has yielded the 8,000-year-old DNA sample.
Once his McMaster lab is up and running, Dr. Poinar will fire up what he calls his "poop factory" to continue the largest coprolite molecular analysis ever, including sexing the ancient stool samples.
"This will be the very first time in the history of paleoanthropology that someone looks at diet and gender differences over hunter-gather populations in the past," he says.
All this would have come as some kind of coprological fantasy to the late Eric Ottleban Callen, whose pioneering coprolite research at McGill University's Macdonald College campus was considered an oddity 50 years ago.
"He endured the frequent ridicule of colleagues in botany and archeology," Dr. Bryant says in a recently published scientific article on Dr. Callen's burgeoning legacy. "Other faculty members at McGill University chastised him for doing coprolite research, which they believed was of little scientific value."
Dr. Poinar believes that his 8,000-year-old DNA dung record is just a sniff of things to come. He has 50,000-year-old Neanderthal feces, from a Spanish cave near Gibraltar, that he believes will help to solve the question of whether the group was able to speak, by revealing whether they had the FOXP2 gene. The gene is necessary for the jaw movements required in speech.
He is also trying to get his hands on the current oldest known hominid fossil feces: 250,000-year-old Homo erectus coprolites from China.
Ironically, Dr. Poinar says, coprolites are turning out to be the respectful way to study the DNA of ancient civilizations, avoiding the need to desecrate the skeletal remains of the ancestors of indigenous peoples.
Dr. Bryant goes so far as to say that it could be through their coprolites that we will best commune with our ancestors, "recreating the very being of individual men and women from DNA, and hormonal evidence left in coprolites, those most personal of artifacts, resonates with the public in a way that even facial reconstruction of skulls cannot."
Jacob Berkowitz is a writer in Almonte, Ont.
Coprolite crusader
The acknowledged father of archeo-logical coprology was a former Second World War spy turned McGill University scientist.
A German-born Scot, Eric Ottleban Callen was a British code breaker who worked with Sir William Stephenson, the Canadian master spy code-named Intrepid, often behind enemy lines. After the war, the University of Edinburgh-trained botanist, specializing in plant fungal diseases, was hired into Canada's only plant pathology department at McGill's bucolic Macdonald College campus.
But Dr. Callen caught coprolite fever. In 1951, a colleague asked him to search for maize pathogens in an ancient Peruvian coprolite.
What he found defined the rest of his life. As he laboured alone in a crammed top-floor lab "no larger than a washroom," in what is now CEGEP John Abbott, he became convinced that coprolites were invaluable biological time capsules. These ancient leavings, he believed, held clues to understanding the fundamentals of ancient human cultures, including class divisions, cooking practices, health, habitats and the rise of agriculture.
His first success, says Vaughn Bryant, an anthropologist at Texas A&M University, was figuring out how to extract delicate microscopic material from hard, desiccated, millennia-old turds. He essentially threw them in the toilet -- a flask in this case -- soaking the coprolites in a solution of trisodium phosphate.
In a seminal 1955 article, Dr. Callen wrote that, "soaking them for 48 hours, . . . they were practically restored to their original consistency."
And in some cases, he believed, also to their original smell (though the jury's still out, and perhaps always will be, on this one).
Analyzing dozens of coprolites from archeological digs in Peru and Mexico, Dr. Callen began to reveal new aspects of the dietary history of New World paleolithic peoples. The findings were both profound and peculiar. From coprolites in Mexico's Tehuacan Valley, he showed that cave dwellers who were subsisting on a millennia-old hunter-gatherer diet lived alongside, and were perhaps the field slaves of, a new urban class that was sitting down to meals of beans, corn and squash.
He also found that some cave dwellers liked their hors d'oeuvre just slightly seared. "Almost the whole skeleton of a harvest mouse was recovered from one coprolite, with the limb bones of one side charred, whilst those on the other were intact," Dr. Callen wrote in Food Habitats of Some Pre-Columbian Mexican Indians.
After two decades as a largely unheralded coprolite crusader, Dr. Callen died in his bedroom-cum-coprolite lab in August, 1970, in the Peruvian mountain town of Ayacucho during his first coprolite field research trip. His journal, collected by Dr. Bryant, notes that he was running out of nitroglycerin tablets and experiencing chest pains. "I must leave soon," he wrote, and underlined, a week before his death.
Since Dr. Callen's death, coprolites have been found to be taxonomic treasure troves, preserving pollen, parasites, algae, viruses, proteins, steroids, seed grains and bones.
-- Jacob Berkowitz