Human Population and Evolutionary Genetics

Almost two decades after the sequencing of the human genome, a deluge of population genomic data has been generated, depicting human genetic diversity at an unprecedented level of resolution. International efforts such as the 1,000 Genomes Project, the Exome Aggregation Consortium or the UK Biobank are providing invaluable resources for understanding the genetic architecture of human diseases and traits. These data have also helped to increase our understanding of the demographic history of our species, including how modern human populations have dispersed around the globe, how population sizes have changed over time and the extent to which they have admixed. Of particular interest over the past few years has been the knowledge we have gained through ancient DNA studies, which have shown that archaic hominins, such as Neanderthals and Denisovans, contributed to the genomes of modern non-African populations. This genetic legacy has been, in some cases, beneficial for the survival of the early modern humans leaving the African continent.

Population genetic studies have also brought new insights into how natural selection, in its different forms, has shaped the patterns of diversity of the human genome at the population scale. Specifically, we have learnt about the mechanisms by which deleterious variants are removed from the population and how the demographic history of a population may affect the efficiency of natural selection to purge deleterious alleles. Genomic studies have also shed new light on how humans have adapted to the broad range of environments they occupy. Indeed, during their dispersals across the globe, humans encountered a highly diverse set of climatic, nutritional, and pathogenic conditions, to which they had to adapt. In this context, the detection of molecular signatures of past selection in the human genome has proved crucial for the identification of genes underlying the morphological and physiological diversity observed across human populations, and for increasing our understanding of the genetic architecture of adaptive traits.

This course aims to provide a basic fundamental knowledge of population and evolutionary genetics applied to humans, and illustrates this field with multiple research examples. We will describe the main drivers of our genetic diversity, including mutation, recombination, genetic drift and natural selection. Furthermore, we will explain how different approaches in population genetics can shed new light onto the demographic history of our species, our dispersals around the world, the occurrence and intensity of admixture with archaic humans and between modern human populations, and genetic adaptation to environmental changes.