It's common belief that Vikings visited Newfoundland, therefore reaching the New World from Europe before Christopher Columbus, but a new genetic analysis claims not only did Vikings visit North America, they brought natives back to Europe with them.  And had babies.

The report in the latest edition of the American Journal of Physical Anthropology says researchers sequenced the complete mitochondrial DNA (mtDNA) genome of 11 people with haplogroup C1, a lineage that was involved in the settlement of North America over 12,000 years ago, from four different families.   No problem, they moved there recently, right?

Maybe not.   Carles Lalueza-Fox said, "But when family genealogy was studied, it was discovered that the four families were descended from ancestors who lived between 1710 and 1740 from the same region of southern Iceland. 

"As the island was virtually isolated from the 10th century, the most likely hypothesis is that these genes corresponded to an Amerindian woman who was brought from America by the Vikings around the year 1000."
 
The 'Icelandic' C1 is not one of the four known Native American (C1b, C1c, and C1d) or Asian (C1a) subclades of haplogroup C1 so they consider it a new subclade, C1e.  

But it's still speculation at this point.

"While a Native American origin seems most likely for C1e, an Asian or European origin cannot be ruled out," they write.

Citation: Sigríður Sunna Ebenesersdóttir, Ásgeir Sigurðsson, Federico Sánchez-Quinto, Carles Lalueza-Fox, Kári Stefánsson and Agnar Helgason, ' A new subclade of mtDNA Haplogroup C1 found in Icelanders: evidence  of  pre‐columbian  contact?  American  Journal  of  Physical  Anthropology,  DOI: 10.1002/AJPA.21419