No one knows what happened to the Dorsets, ancient Paleo-Eskimos that lived thousands of years ago and then seemed to suddenly vanish 700 years ago. The Dorsets lived in the Arctic region, and spread from Greenland to parts of arctic Canada.

In a paper published on August 28 in the journal Science, researchers explore what happened to the ancient Eskimos. A team researched 169 DNA samples from the Dorset people to learn more about their migration habits. The study was a collaboration of more than 50 scientists, from international backgrounds. They found that the Dorset people were a single population that was genetically different from other groups, and existed for at least 4,000 years, then seemed to suddenly disappear. The Dorset people descended from a group that traveled in from Siberia. Modern people who live in the Arctic region are descended from separate groups of people.

This study is the most complete genetic look that has ever been done about people who lived in the Arctic region thousands of years ago. Before this study, most research about these people was based on cultural artifacts. DNA can tell us with much more precision how this group evolved.

There has been a lot of arguing in the past about the Arctic people's lineage and scientists could never seem to all agree.

"Since the 1920s or so, it has been heavily discussed what is the relationship between these cultural groups," said Professior Eske Willerslev, a senior author of the paper, who works at the Natural History Museum of Denmark, part of the University of Copenhagen.

Willerslev said that many theories about the Arctic people had been brought up, from the modern Inuit people being directly descended from ancient Paleo-Eskimos, to other people who suggested that the Saqqaq, Dorset and Thule groups were distinct groups of people.

The new research suggests that the Dorset tribe is descended from the Saqqaq people. The earliest Saqqaqs migrated to the Arctic from Siberia over 6,000 years ago.

"A single founding population settled, and endured the harsh environmental conditions of the Arctic, for almost 5,000 years - during which time the culture and lifestyle changed enough to be represented as distinct cultural units," said Dr Maanasa Raghavan, the lead author on the paper.

All three tribes lived in the same place, in northern North America. The Saqqaq tribe died out about 2,500 years ago. Then Dorset people lived in the area, followed by the Thule group. Modern Inuits are descended from members of the Thule.