Researchers affiliated with institutions in the USA, Europe, and South America have found evidence that suggests the native people of South America likely arrived from more than one place. For many years, it was believed that a single wave of ancient immigrants made their way from Asia to North America and eventually to South America.
     To learn more about the ancestry of some of the earliest settlers to South America, the researchers examined skulls found in Lagoa Santa, Brazil. Prior research had dated the skulls back 7,000 to 10,000 years - near the time when scientists believe South America was first populated by humans. The researchers report that the skull shapes of the ancient people differed markedly from those of modern indigenous South Americans.
     One of the group was also part of another team that recently imaged 500 to 800-year-old (pre-Conquest) skulls from two of three distinct regions in Mexico, two of which matched one another but not the third.
     Most experts in the field believe that at least one wave of immigrants came across the Bering Strait. Some have suggested other immigrants may have arrived from Australia.
     The nature and timing of the peopling of the Americas is a subject of intense debate. It is unclear whether high levels of diversity in South America result from multiple migrations. Previous hypotheses largely focused on alternative gene flow models, with conflicting or inconclusive results. This latest effort shows that Palaeo-Americans share a last common ancestor with contemporary Native American groups outside the Americas, suggesting that the continents were populated by multiple waves from northeast Asia throughout the late Pleistocene and early Holocene.

Edited from PhysOrg (23 February 2017)