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Scientists know that about 200,000 years ago, the Earth experienced a glacial period and our ancestors migrated from africa. But they don’t know exactly how the planet’s changing climate affected mammoths and other large animals during this time. What is also unclear is how its arrival in North America altered the genetic diversity of mammoths.
Dr. “We don’t know much about what was going on at that time,” Fisher said. “We don’t have access to many samples from this period, and this is largely because sediments from this era are difficult to access.”
Mammoths, the furry, small-eared relatives of modern elephants, first appeared about five million years ago and went extinct about 4,000 years ago. The first mammoths came out of Africa and spread north, evolving into different species along the way until they colonized most of the Northern Hemisphere.
The earliest mammoths to enter North America were known as Krestovka or steppe mammoths. These mammoths came from Eurasia 1.5 million years ago and crossed the Bering Strait on foot, which was not covered with water as it is today. Hundreds of thousands of years later, another mammoth species, the woolly mammoth, also crossed the Bering Strait and joined its North American cousins. The two interbred to produce the Columbian mammoth, but no one knows exactly when. A recent study has shown that hybridization the event occurred at least 420,000 years ago, but more research is needed to confirm this.
If the tooth is as old as scientists suspect, “it could really help clarify the timing of this hybridization event,” said Pete Heintzman, associate professor who studies the DNA of mammoths and other ice age creatures at the Norwegian Arctic University Museum.
Although exposure to salt water can damage biological tissue, the deep sea can be ideal for DNA preservation.
Not involved in the ongoing analysis of the tooth, Dr. “It’s dark, cold, and environmentally stable,” Heintzman said. The best-preserved remains typically come from permafrost and caves that have low, stable temperatures, such as the deep sea, and are dimly lit.
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