Tracing the peopling of the world through genomics

Abstract

Advances in the sequencing and the analysis of the genomes of both modern and ancient peoples have facilitated a number of breakthroughs in our understanding of human evolutionary history. These include the discovery of interbreeding between anatomically modern humans and extinct hominins; the development of an increasingly detailed description of the complex dispersal of modern humans out of Africa and their population expansion worldwide; and the characterization of many of the genetic adaptions of humans to local environmental conditions. Our interpretation of the evolutionary history and adaptation of humans is being transformed by analyses of these new genomic data.

Figure 1. Timeline of important milestones in human evolutionary genomics

A large number of studies have contributed important insights into human history using genomic data; those of particular influence in terms of the data or data analyses that they present are shown.

Figure 2. Simplified model of human evolutionary history

Relationships between contemporary populations and the approximate times at which they diverged are shown. These include important well established (solid lines) and tentative (dashed lines) admixture events between groups of modern humans and between modern and archaic humans. The model also shows the potential small proportion of ancestry in Oceanic populations that is derived from an early out-of-Africa migration (turquoise). Studies of ancient DNA can provide high-resolution insights into the history of populations and have revealed that present-day Europeans comprise admixture between three ancestral groups (inset). ANE, ancient north Eurasian; EEF, early European farmer; WHG, west European hunter-gatherer.

Figure 3. Major human migrations across the world inferred through analyses of genomic data

Some migration routes remain under debate. For example, there is still some uncertainty regarding the migration routes used to populate the Americas. Genomic data are limited in their resolution to determine paths of migration because further population movements, subsequent to the initial migrations, may obscure the geographic patterns that can be discerned from the genomic data. Proposed routes of migration that remain controversial are indicated by dashed lines. CA, Central Anatolia; FC, Fertile Crescent; IP, Iberian Peninsula; PCS, Pontic–Caspian steppe.