Testing Evolutionary and Dispersion Scenarios for the Settlement of the New World

Abstract

BackgroundDiscussion surrounding the settlement of the New World has recently gained momentum with advances in molecular biology, archaeology and bioanthropology. Recent evidence from these diverse fields is found to support different colonization scenarios. The currently available genetic evidence suggests a “single migration” model, in which both early and later Native American groups derive from one expansion event into the continent. In contrast, the pronounced anatomical differences between early and late Native American populations have led others to propose more complex scenarios, involving separate colonization events of the New World and a distinct origin for these groups.Methodology/Principal FindingsUsing large samples of Early American crania, we: 1) calculated the rate of morphological differentiation between Early and Late American samples under three different time divergence assumptions, and compared our findings to the predicted morphological differentiation under neutral conditions in each case; and 2) further tested three dispersal scenarios for the colonization of the New World by comparing the morphological distances among early and late Amerindians, East Asians, Australo-Melanesians and early modern humans from Asia to geographical distances associated with each dispersion model. Results indicate that the assumption of a last shared common ancestor outside the continent better explains the observed morphological differences between early and late American groups. This result is corroborated by our finding that a model comprising two Asian waves of migration coming through Bering into the Americas fits the cranial anatomical evidence best, especially when the effects of diversifying selection to climate are taken into account.ConclusionsWe conclude that the morphological diversity documented through time in the New World is best accounted for by a model postulating two waves of human expansion into the continent originating in East Asia and entering through Beringia.

Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia

“…In the case of the genetic dataset, the control and MDI models were significant after Bonferroni correction for multiple model tests, although the MDI correlation coefficient was almost twice as large as that of the control model. A Dow-Cheverud test (22,24) indeed differentiates MDI as a better model against the control (r = 0.588, P ≤ 0.0001).…”

“…Latitude and longitude coordinates (Table 1) are an approximate centroid for each population, although we placed both African samples at Addis Ababa, Ethiopia to avoid assumptions about internal migrations within the continent. Our control model was calculated using the pairwise geodesic distances between populations, without consideration for geographical barriers (24). Waypoints were used in the other models to represent the complex geography of hypothetical dispersal routes ( Fig.…”

“…The partial Mantel test (Table 3) assessed the correlation of the pairwise biological population differentiation values (F st or P st ) against the dispersal models (G), while controlling for population divergence values (T). To assess whether one model could be favored over another when more than one competing model was correlated significantly after Bonferroni correction for multiple model tests, we conducted a DowCheverud test (22,24). In all cases, we ran 10,000 permutations to assess correlation significance.…”

Serum testosterone levels and excessive erythrocytosis during the process of adaptation to high altitudes

“…The migration to the Americas seems to have occurred during the last Ice Age, from Asia to North America through the Bering Strait. 6 In Peru, most findings suggest that the first presence of humans in the highlands occurred between 12 000 and 13 000 years BC. 7 The Spanish conquest of Peru occurred in the sixteenth century.…”

Morfologia craniana dos remanescentes ósseos humanos da Lapa do Santo, Lagoa Santa, Minas Gerais, Brasil: implicações para o povoamento das Américas

“…Os resultados obtidos neste trabalho apoiam estudos anteriores (Neves e Hubbe, 2005;Neves et al, 2004Neves et al, , 2007bNeves et al, , 2007cBernardo, 2007;Bernardo e Neves, 2009;Hubbe et al, 2010Hubbe et al, , 2011Bernardo et al, 2011), que mostram uma grande afinidade morfológica entre os grupos de Lagoa Santa e séries australo-melanésias, e, em segundo lugar, com os povos africanos representados nas séries Howells. Em contraparte, os crânios de populações nativas americanas recentes (Arikara, Santa Cruz e Peru) ocupam uma posição completamente oposta no morfoespaço, agrupando-se com populações da Ásia, da Polinésia e da Europa, à exceção dos habitantes tardios da ilha de Páscoa, que mostram maior afinidade ao material de Lagoa Santa.…”