DNA research has come a long way in the past 5 years.
The science is here to explain it. High level summary. Native American Indians, Canadian First People, south American Indians. They have a genetic trail. 6 waves of migrations from east Asia. Some over the arctic alaska land bridge, some by sea on the pacific ocean. Just like the Japanese Tsunami wreckage washed up 3 months later on the US west coast.
But the interesting thing is about 10,000+ years ago, the Indians from India, similar to the Roma indian gypsies, went north to China, further north to Russia, mixed with the locals then moved a little further north then east to the Americas.
Then with the Spaniards in North America, that brought in a cocktail of the genetic Moors (arabs) to the mix of the Chinese and Hindu indians to what is now known as the the Native Americans Indians.
Weirdness is that some Mexicans genetic tests came out with Russians ancestry, before the lab adjusted for the variance.
Even stranger is that native american indians have some ancester roots to Hindu India. Sort of explains how Columbus jumped to that eroneous conclusion.
Testing is a lot cheaper now, about $50. They send you a qtip to swab the inside of your mouth.