Human Population Genetics and Genomics

Alan R. Templeton

• Publisher: Academic Press
• Year: 2018
• Print ISBN: 9780123860255
• eBook ISBN: 9780123860262
• Topic: Biological Sciences
• Subtopic: Biology
• Index: Biological Sciences

Human Population Genetics and Genomics provides researchers/students with knowledge on population genetics and relevant statistical approaches to help them become more effective users of modern genetic, genomic and statistical tools. In-depth chapters offer thorough discussions of systems of mating, genetic drift, gene flow and subdivided populations, human population history, genotype and phenotype, detecting selection, units and targets of natural selection, adaptation to temporally and spatially variable environments, selection in age-structured populations, and genomics and society. As human genetics and genomics research often employs tools and approaches derived from population genetics, this book helps users understand the basic principles of these tools.In addition, studies often employ statistical approaches and analysis, so an understanding of basic statistical theory is also needed.- Comprehensively explains the use of population genetics and genomics in medical applications and research- Discusses the relevance of population genetics and genomics to major social issues, including race and the dangers of modern eugenics proposals- Provides an overview of how population genetics and genomics helps us understand where we came from as a species and how we evolved into who we are now

Chapter 1

Definition, Scope, and Premises of Human Population Genetics

Abstract

Population genetics is the science of genetic variation within populations of organisms. Population genetics focuses on the origin, amount, frequency, distribution in space and time, and phenotypic significance of that genetic variation, and with the microevolutionary forces that influence the fate of genetic variation in reproducing populations. The extensive theoretical edifice of this field stems from three premises: DNA can replicate, DNA mutates and recombines, and the information in DNA interacts with the environment to produce traits. DNA replication means that a single type of gene can exist in space and time (across generations) beyond any individual who bears the gene. This means that the fate of genes in space and time must be studied at the level of a reproducing population and its associated gene pool—the population of gametes that are the bridges across the generations. Mutation and recombination ensure that the gene pool consists of a variety of genetic types and is the physical basis of all evolutionary change. One of the most important attributes of evolution is adaptation, the acquiring of traits that allow individuals to survive, mate, and reproduce in a particular environment. Adaptation can only occur because the traits emerge from an interaction of genes and environment.

Keywords

Bayesian statistics; Evolution; Gene pool; Genotype; Haplotype; Linkage disequilibrium; Maximum likelihood; Mutation; Natural selection; Phenotype; Recombination

Population genetics is the science of genetic variation within populations of organisms. Population genetics is concerned with the origin, amount, frequency, distribution in space and time, and phenotypic significance of that genetic variation, and with the microevolutionary forces that influence the fate of genetic variation in reproducing populations. Human population genetics is specifically concerned with genetic variation in human populations and its evolutionary and phenotypic significance. Although most population genetic principles are broadly applicable to many species, there are many compelling reasons to focus on our own species. First, we are simply interested in ourselves; we are curious about our origins and how we got to be who we are today. Population genetics can provide insights into the roots of us all.

Second, all species are unique in some respect, but the human species is unique in many important ways. As will be discussed in later chapters, our species has undergone several major range expansions over the last two million years. These range expansions have made us one of the most widely distributed species on the planet and these historical expansions have left a genetic signature on the variation that we carry in our collective gene pool today. Starting about 10,000 years ago with the invention of agriculture, our species has also sustained superexponential population growth, making us one the most abundant large-bodied species on the planet. As we will see, this sustained population growth over such a long period of time has strongly influenced our spectrum of genetic variation in a manner found in almost no other species. Many species can define or shape the environments in which they live to some extent, but our species has taken it to an extreme. Because of our intelligence, we define our environments through culture, with our cultural environments changing at an increasing rate. As we will see, there are strong interactions between genes and genomes with environments (including culture), and these emerge as a unique aspect of our population genetics. Indeed, because of our widespread geographical distribution, numerical abundance, and cultural impacts, the human species can and is changing the environment at the global level, thereby making humans a keystone species that influences the existence and evolutionary fate of many other species that coinhabit the Earth with us. A final unique aspect of our species is our social behavior. Only a handful of species have evolved advanced social behavior, and humans are one of that handful. Complex social environments can also interact with genes, adding another dimension to human population genetics and evolution.

A third reason for focusing on human population genetics is practical. We live in an era in which genetics and genomics are increasingly having an impact on medicine and human health. Many of the tools for these practical applications of genetics and genomics come from population genetics. Medical research is often about variation within populations: why are some people healthy and others not; why do some people get disease X and othe...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Preface
• Chapter 1. Definition, Scope, and Premises of Human Population Genetics
• Chapter 2. The Human Genome
• Chapter 3. Systems of Mating
• Chapter 4. Genetic Drift
• Chapter 5. A Backward View of Genetic Drift: Coalescence
• Chapter 6. Gene Flow and Subdivided Populations
• Chapter 7. Human Population History Over the Last Two Million Years
• Chapter 8. Genotype and Phenotype
• Chapter 9. Natural Selection
• Chapter 10. Detecting Selection Through Its Interactions With Other Evolutionary Forces
• Chapter 11. Units and Targets of Natural Selection
• Chapter 12. Human Adaptations to Temporally and Spatially Variable Environments
• Chapter 13. Selection in Age-Structured Populations
• Chapter 14. Human Population Genetics/Genomics and Society
• Index