The genetic and evolutionary basis of gene expression variation in East Africans.

Background: Mapping of quantitative trait loci (QTL) associated with molecular phenotypes is a powerful approach for identifying the genes and molecular mechanisms underlying human traits and diseases, though most studies have focused on individuals of European descent. While important progress has been made to study a greater diversity of human populations, many groups remain unstudied, particularly among indigenous populations within Africa. To better understand the genetics of gene regulation in East Africans, we perform expression and splicing QTL mapping in whole blood from a cohort of 162 diverse Africans from Ethiopia and Tanzania.

Correction to: African evolutionary history inferred from whole genome sequence data of 44 indigenous African populations.

Following publication of the original article [1], a typographical error in the formula for calculating d in the "Scans for local adaptation" subsection in the Method section, was identified. The correct formula should be.

African evolutionary history inferred from whole genome sequence data of 44 indigenous African populations.

Background: Africa is the origin of modern humans within the past 300 thousand years. To infer the complex demographic history of African populations and adaptation to diverse environments, we sequenced the genomes of 92 individuals from 44 indigenous African populations.

Results: Genetic structure analyses indicate that among Africans, genetic ancestry is largely partitioned by geography and language, though we observe mixed ancestry in many individuals, consistent with both short- and long-range migration events followed by admixture.

Loci associated with skin pigmentation identified in African populations.

Despite the wide range of skin pigmentation in humans, little is known about its genetic basis in global populations. Examining ethnically diverse African genomes, we identify variants in or near , , , , , and that are significantly associated with skin pigmentation. Genetic evidence indicates that the light pigmentation variant at was introduced into East Africa by gene flow from non-Africans.

Global variation in gene expression and the value of diverse sampling.

The genomics era has accelerated our understanding of how genetic and epigenetic factors influence both normal variable traits and disease risk in humans. However, the majority of "omics" studies have focused on individuals living in urban centers, primarily from Europe and Asia, neglecting much of the genetic and environmental variation that exists across worldwide populations. Comparative studies of gene regulation in ethnically diverse populations are informing our understanding of how evolutionary forces have shaped the genetic and molecular mechanisms underlying complex traits, and studying gene expression in different environmental contexts is enabling the dissection of disease-related pathways such as immune response.