The Genetic Diversity of the Americas

Abstract

The history of the Americas involved the encounter of millions of Native Americans, Europeans, and Africans. A variable admixture of these three continental groups has taken place between them throughout the continent, influenced by demography and a range of social factors. These events have had a major influence on the genetic makeup of populations across the continent. Here, we summarize the demographic history of the region, highlight some social factors that affected historical admixture, and review major patterns of diversity across the Western Hemisphere based on genetic data.2

Breast cancer subtypes among Eastern‐African–born black women and other black women in the United States

“…characteristics, including stage, grade, and histology. 10,11,22 Yet nativity and geographic origin among black women has seldom been examined, although considering nativity-related differences may improve our understanding of the etiologic heterogeneity of breast cancer. This finding suggests that the typical notion of higher proportional burden of triple-negative breast cancer among black women is not generalizable to all women of African descent.…”

“…[6][7][8] However, "African ancestry" represented by AIMs was suggested by samples predominantly collected in West Africa, 9 limiting the ability to capture the diverse ancestral components in the remaining regions of Africa and to adjust population stratification in admixed populations. Moreover, recent studies have reported that individuals who self-identify as black or African American have the highest level of within-population genetic diversity of all racial/ethnic groups in the United States, 10,11 likely a reflection of greater genetic admixture that has been shaped by various social factors, including historical migrations across and within continents. This suggests that racial category may be too broad to accurately characterize breast cancer subtype distribution, particularly among women with African ancestry.…”

Latin Americans show wide-spread Converso ancestry and the imprint of local Native ancestry on physical appearance

“…Historical records and genetic analyses indicate that Latin Americans trace their ancestry mainly to the admixture of Native Americans, Europeans and Sub-Saharan Africans 1 . Using novel haplotype-based methods here we infer the sub-populations involved in admixture for over 6,500 Latin Americans and evaluate the impact of subcontinental ancestry on the physical appearance of these individuals.…”

“…Since this was a clandestine process, the extent of Converso migration to Latin America is poorly documented. Genetic studies have provided suggestive evidence that certain Latin American populations, arguably with a peculiar history, could have substantial Converso ancestry 1,18 . Our findings indicate that the genetic signature of Converso migration to Latin America is substantially more prevalent than suggested by these special cases, or by historical records.…”

Factores de riesgo de la enfermedad por hígado graso no alcohólico en poblaciones de Latinoamérica: situación actual y perspectivas

“…en un estudio realizado en Argentina con 258 varones voluntarios sanos no emparentados, identificaron el genotipo GG de PNPLA3 rs738409 en el 63,7 % de las personas con ascendencia materna y paterna nativa americana. Es importante considerar que la mezcla de nativos americanos, europeos y africanos es variable en toda Latinoamérica, lo que hace que la composición genética de cada país sea notablemente heterogénea. Por ejemplo, en la población brasileña se ha observado una mayor contribución de la ascendencia genética africana, mientras que en Bolivia, Perú, México, Ecuador, Chile y Colombia predomina la contribución de la ascendencia nativa americana.…”