As if the natives didn't?
Read about the Beaver Wars. Most of the native populations that were here before the English got here are dead. If disease (and remember, plagues took out a number of Europeans, too, so that's an equal opportunity killer) didn't get them, other tribes did. The current tribes emigrated from one area to another just as much as whites did. The small Iroquois tribe, for example, controlled almost all of the Ohio and upper Mississippi valleys ca. 1700, an area far greater than the English controlled on the East Coast, and the Iroquois' pre-European contact "homeland" was actually far smaller, roughly corresponding to modern Central New York.
And for the record, the Fuller family arrived here in the 1620s and 1630s, before the Iroquois went on their sprees.
There is a lot of America to the west. The Plains, Southwest, Northeast all had tribes. Contact with natives in North America was made by the Spanish first.
What took place in New England and the Atlantic coastal strip of colonies was just a fraction of the entire story.
Throughout our history, native Americans were treated badly, tricked, cheated. Canada treated their First Nation's citizens better.
As to their origins, they migrated to North America, too.
One of my direct ancestors was killed by Indians in Maine in 1706, together with his brother. They had come to North America from the English Channel Islands, however they were nearly certain originally Catalonian, from Spain or France-based on their surname. The Channel Islands were a place where Protestants fled during the Spanish and French inquisitions. Possibly some Jews, too.
Another direct ancestor was killed in Spencer County Indiana in 1820, and his son was wounded (both my great grandfathers-too much work to count "Gs".
My grandfather, born 1881 in South Dakota grew up around Indians, and wore an Indian bracelet until his death age 86. He was the son of two immigrants from Sweden.
For centuries their has been intermarriage between Hispanics and Indians all across the Southwest.
