Is everyone Asian?

An article title “The ‘first Americans’ probably weren’t”, published by Reuters, claims that the Clovis people were not the first to arrive in the Americas and that they probably arrived much the same time as other cultures.

According to Michael Waters, director of Texas A&M University’s Center for the Study of the First Americans, and one of the two authors of the research paper dating the Clovis people back 13,100 to 12,900 years ago, the first people to arrive in the Americas came between 25,000 and 15,000 years ago.

“And we have to start now thinking about the peopling of the Americas as a process, with people coming over here, probably arriving at different times, maybe taking different routes and coming from different places in northeast Asia.”

What I find interesting is that everyone is assumed as coming from Asia. Is it possible that mankind could have developed on both continents at the same time? If we are to believe Darwin's Theory of Evolution then there is no reason to assume to assume mankind could have only evolved from Asian traits.