Where did the first people to populate the Americas come from?

The first people to populate the Americas most likely came from East Asia. Historians, archaeologists, and biologists have performed extensive studies of the culture and DNA of indigenous Americans. These studies have led them to conclude that indigenous Americans most likely crossed from Russia into Alaska via the Bering Strait, a now-submerged land bridge in the Bering Sea. According to a gene study profiled in USA Today, this migration took place in three waves: 30,000; 16,000; and 15,000 years ago. After reaching North America, they gradually migrated south.
Interestingly, a recent gene study indicated that indigenous Americans have genomes that contain many similarities to those of west Eurasians. This seems to indicate that some of the Bering Strait migrant populations actually originated in the Middle East and Europe, rather than solely in East Asia.
http://usatoday30.usatoday.com/tech/science/story/2012-07-11/native-american-origins/56148248/1

https://www.nationalgeographic.com/news/2013/11/131120-science-native-american-people-migration-siberia-genetics/