Ann,
I posted links to two stories about how the DNA from ancient bodies were linked to the DNA of currently living Alaska Natives. The bones were found on Prince of Wales Island. 
Proof that the ancestors of today's 3 SE tribes  were here thousands of years ago, 10,300 years ago. 
https://www.adn.com/alaska-news/science/2017/04/16/an-ancient-skeleton-reveals-a-10000-year-old-native-link-to-southeast-alaska/
http://www.sciencemag.org/news/2017/04/ancient-skeletons-show-direct-link-modern-tribes-pacific-northwest