SCIENCE / MOLECULAR BIOLOGY : Old Blood Yields Clues to Ancient Species
About 200,000 years ago, an artisan who lived along a river in northwestern Iraq made a flint scraper, used it to carve and shape a pine tree, then threw it away.
While using it, he cut himself. His blood is still on the flint, which now is the property of the Oriental Institute in Chicago. Using new techniques of molecular biology, Australian anthropologist Thomas H. Loy has proved that the blood is human.
Such techniques, reported Friday at a meeting of the American Assn. for the Advancement of Science, are leading to more precise dating of blood and promise to shed light on ancient species.
Loy, of the Australian National University in Canberra, told meeting participants that the blood most likely is from a Neanderthal, an early human believed to have become extinct when it could not compete with modern humans.
Loy believes there is enough blood on the flint to perform a genetic analysis, which, he said, would allow a comparison of more modern humans’ and Neanderthals’ genetics for the first time. Loy and his colleagues are refining their procedures before they attempt a comparison.
“This gives us a window back into the past that we’ve never had before,” Loy said.
Elsewhere, researchers are using these new techniques to study preserved animal blood on arrow tips and spear points to determine which species early humans hunted.
Surprisingly, they have found that animal blood and proteins can be preserved remarkably well, and these ancient specimens have the potential to provide a great deal of information that is unavailable through other archeological techniques.
Human blood and proteins can show up in surprising places. Many cave painters mixed their blood into pigments. By studying the blood, archeologists believe they can trace the movements of peoples around the world and learn about some cultural traditions, such as whether males or females did the painting.
New, highly sensitive dating techniques requiring only small amounts of carbon can be used on blood found on tools and in paint to provide the first direct dates for the artifacts, instead of relying on the age of other remains, such as fire pits, found in the same context.
Studies of animal blood can provide several types of evidence. Archeologist Margaret E. Newman of Cal State Bakersfield reported that she had studied blood on 440 stone artifacts, dating from about 5,400 years ago, taken from Hidden Cave on the north side of Eetza Mountain in Nevada.
Most of the blood was from species that the cave’s residents were known to exploit. But she also found blood from four types of large animals--cats, sheep, buffaloes and bears--that were not thought to be in the area at that time. Her findings, she said, indicate that “they either were present in the area in the past or that prehistoric people practiced long-distance hunting or trade as part of their subsistence strategies.”
Similarly, Loy studied blood on 22 chert knives recovered from a site near the northern terminus of the Rocky Mountains in western Canada. Along with blood from sheep, caribou, moose and bears, he found blood from buffaloes on the 2,200-year-old knives.
Buffaloes, however, are no longer found in the region and were not thought to be part of that area’s food supply. Indeed, there is no word for buffalo in the local Athabascan language, nor is there any ethnographic record of buffalo hunting.
“But now we know,” he said, “that 2,165 years ago, somebody butchered a bison.” Anthropologists will thus have to rethink their ideas about the life of the Athabascan peoples.
Climatic information can be deduced from animal blood, said archeologist David D. Hyland of Mercyhurst College in Erie, Pa., who is studying blood on 11,000-year-old spear points collected from a site along the Pennsylvania River.
Preliminary results indicate that the blood is from either deer or caribou, he said, and he is trying to determine which. If the blood is from caribou, a cold-weather animal, then glaciers were probably very close to the site, he said. But if the blood is from deer, which live in warmer climates, the glaciers were undoubtedly further north.
The studies can also provide information about human health. Archeologist Noreen Tuross of the Smithsonian Institution studied antibodies isolated from human bones about 1,250 years old. The bones suggested that the individual had been infested with parasites known as treponemes. Tuross said that she found antibodies specific for treponemes, confirming the original diagnosis.
Studies of animal blood and proteins are still in their infancy, but researchers are confident that they will provide valuable information. Loy hopes that studies of blood in Australian cave paintings will solve the dispute over the geographic origin of aborigines. “This field has a great future,” he said.
