Abstract
BackgroundWe re-assess support for our three stage model for the peopling of the Americas in light of a recent report that identified nine non-Native American mitochondrial genome sequences that should not have been included in our initial analysis. Removal of these sequences results in the elimination of an early (i.e. ∼40,000 years ago) expansion signal we had proposed for the proto-Amerind population.Methodology/FindingsBayesian skyline plot analysis of a new dataset of Native American mitochondrial coding genomes confirms the absence of an early expansion signal for the proto-Amerind population and allows us to reduce the variation around our estimate of the New World founder population size. In addition, genetic variants that define New World founder haplogroups are used to estimate the amount of time required between divergence of proto-Amerinds from the Asian gene pool and expansion into the New World.Conclusions/SignificanceThe period of population isolation required for the generation of New World mitochondrial founder haplogroup-defining genetic variants makes the existence of three stages of colonization a logical conclusion. Thus, our three stage model remains an important and useful working hypothesis for researchers interested in the peopling of the Americas and the processes of colonization.
Highlights
We recently published a three stage model for the peopling of the Americas [1]
It appears that the non-Native American sequences introduced additional variation that created an expansion signal that does not exist in an analysis of only Native American sequences
The absence of an early expansion signal in the skyline plot may indicate that divergence of proto-Amerinds from the Asian gene pool was not accompanied by significant population growth
Summary
We recently published a three stage model for the peopling of the Americas [1]. we proposed that a recent, rapid expansion into the Americas was preceded by a long period of population stability in greater Beringia by the proto-Amerind population after divergence from their ancestral Asian population. Fagundes et al [4] have published a re-analysis of the data we used in developing our three stage model for the peopling of the Americas [1] They identified nine mitochondrial coding region sequences that we assumed were Native American sequences, but instead are likely to derive from Asian or European individuals. The effect of removing these sequences from the Bayesian skyline plot analysis is that the suggestion of an early expansion event in the skyline plot is no longer apparent, a finding that we have reconfirmed by re-running our original dataset without these nine genomes It appears that the non-Native American sequences introduced additional variation that created an expansion signal that does not exist in an analysis of only Native American sequences. As in our previous analysis, we evaluate the significance of our results in concert with other non-genetic data
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
