Key quotes:

Ten years ago, Agnar Helgason, a scientist at Iceland’s deCODE Genetics, began investigating the origin of the Icelandic population. Most of the people he tested carried genetic links to either Scandinavians or people from the British Isles. But a small group of Icelanders — roughly 350 in total — carried a lineage known as C1, usually seen only in Asians and Native Americans.

… all the people who carry the C1 lineage are descendants of one of four women alive around the year 1700. In all likelihood, those four descended from a single woman. And because archeological remains in what is Canada today suggest that the Vikings were in the Americas around the year 1000 before retreating into a period of global isolation, the best explanation for that errant lineage lies with an American Indian woman: one who was taken back to Iceland some 500 years before Columbus set sail for the New World in 1492.

I love this kind of stuff.