The Paleo-Indian Entry into South America According to Mitogenomes

Recent and compelling archaeological evidence attests to human presence 14.5 ka at multiple sites in South America
and a very early exploitation of extreme high-altitude Andean environments. Considering that, according to genetic
evidence, human entry into North America from Beringia most likely occurred 16 ka, these archeological findings
would imply an extremely rapid spread along the double continent. To shed light on this issue from a genetic perspective,
we first completely sequenced 217 novel modern mitogenomes of Native American ancestry from the northwestern area
of South America (Ecuador and Peru); we then evaluated them phylogenetically together with other available mitogenomes
(430 samples, both modern and ancient) from the same geographic area and, finally, with all closely related
mitogenomes from the entire double continent. We detected a large number (N¼ 48) of novel subhaplogroups, often
branching into further subclades, belonging to two classes: those that arose in South America early after its peopling and
those that instead originated in North or Central America and reached South America with the first settlers. Coalescence
age estimates for these subhaplogroups provide time boundaries indicating that early Paleo-Indians probably moved
from North America to the area corresponding to modern Ecuador and Peru over the short time frame of 1.5 ka
comprised between 16.0 and 14.6 ka.