Ummm. Thats where they came from....
Its called the beringia land bridge. Its how they came from the uncivilized west
, to the new land now called north america.
See man came stumbling out of a forest, or a cave, well a uterus somewhere near mesopotamia or africa. As these small hunting and gathering groups flourised, divided, participated in osmosis, and divided again, smaller groups ventured outward beginning whats called emigration, or immigration. Eventually some group ended up hitting that fucking bridge right at the right time, and old man silver carried them across the bridge and set them down on the other side, never to be seen again. Well these people scaled down and across the continent very effectively creating small-medium sized bands and nations that both practiced hunting and gathering and certain types of agriculture.
Clearly man didn't happen to come from 2 completely different sources on different continents and we share near identical traits, besides culture. Or maybe they are the egytians that come across, or some jewish slaves of egyptians, OMG!!! Joseph Smith was right!!!
Peace