Prehistoric DNA extracted from Ice Age camel fossils discovered in the Yukon of Canada reveals that – despite how they look – the animals are more closely related to today’s camels in Africa and Asia than to South American alpacas and llamas. The findings, published in Molecular Biology and Evolution last week, rewrite the evolutionary history of the camel family.
Until about 13,000 years ago, western camels, Camelops cf. hesternus, used to roam western and central North America. They had a single hump, a long neck, and long legs. According to paleontologist Grant Zazula with the Government of Yukon, researchers thought late Pleistocene western camels were like “giant llamas” or “llamas on steroids.” For years, the animals were thought to be closely related to the modern camelids of South America: llamas, guanacos, alpacas, and vicuñas.
Based on radiocarbon dating, Ice Age western camels living in the southern parts of North America migrated north into Alaska and the Yukon just once, about 100,000 years ago, during a brief period of warmer temperatures. They went extinct around the end of the Ice Age, and because so few of them ventured so far north, camel fossils in the arctic are very rare. But those that have been discovered were preserved in permafrost – which means that DNA can be extracted.
In 2008, miners hydraulically stripping the ground in the Klondike gold fields near Dawson City in the Yukon uncovered three fossils. “We couldn’t care less about the gold,” Zazula says. “For us the gold is the fossils because it’s this incredible resource for understanding extinct and ancient animals of the Ice Age. It’s really our gold mine for sure.”
When he and a team led by Peter Heintzman from the University of California, Santa Cruz, analyzed the fossils and the genomic data contained within, they found that the Ice Age camels are more closely tied to modern camels living in Asia, Arabia and Africa than they are to the alpacas and llamas that they resemble. The molecular data also suggests that western camels split off from the branch that includes today’s camels about 10 million years ago or so, in the Late Miocene.
"With ancient DNA and genetic technologies now, we can actually reveal a whole lot more about their history, and sometimes animals that look like one another may not be even closely related at all," Zazula adds. "And that's what we're discovering with this."
[Via The Globe and Mail]
Images: Government of Yukon