Traci Watson for National Geographic News:

Five hundred years before Columbus sailed the ocean blue, a Native American woman may have voyaged to Europe with Vikings, according to a provocative new DNA study.

Analyzing a type of DNA passed only from mother to child, scientists found more than 80 living Icelanders with a genetic variation similar to one found mostly in Native Americans.

[…]

Historical accounts and archaeological evidence show that Icelandic Vikings reached Greenland just before 1000 and quickly pushed on to what is now Canada. Icelanders even established a village in Newfoundland, though it lasted only a decade or so.