Population Genetics

by

A. Rus Hoelzel

• LAST REVIEWED: 15 January 2020
• LAST MODIFIED: 15 January 2020
• DOI: 10.1093/obo/9780199941728-0051

Introduction

The molecule that determines life, deoxyribonucleic acid (DNA), can be usefully divided up into segments called “loci” (just the position of a stretch of DNA), at which the DNA itself is known as an “allele.” The pair of alleles at a locus in a “diploid” organism (with two complements of the nuclear genome as pairs of chromosomes) is called a “genotype.” Population genetics is the study of alleles and genotypes in natural and experimental populations, and the associated theoretical considerations that determine their relative frequency in space and time. It describes how the raw material of evolution (variant genotypes in natural populations, introduced by mutation, recombination, or migration) provides the resource for the process of evolution. The two key evolutionary processes that influence allele frequencies across generations are natural selection, which is based on the differential representation of genotypes in the next generation through successful reproduction, and genetic drift, based on the chance survival or extinction of alleles in populations of finite size. The broader objectives of population genetics include an understanding of alleles that segregate (remain within a population), the effects of recombination and mutation, and the influence of factors such as population size, migration, mating behavior, natural selection, and genetic drift.

General Overviews

There are a number of useful overviews of population genetics, ranging from the introductory primer Gillespie 2004 through standard textbooks such as Hartl and Clark 2007 and Hedrick 2010. For a historical perspective, Provine 2001 provides a useful summary of the theoretical aspects, especially on the history associated with the Hardy-Weinberg rule. Looking forward, Allendorf, et al. 2012 provides an introduction to some of the important applied aspects of the field.

• Allendorf, Fred W., Gordon H. Luikart, and Sally N. Aitken. 2012. Conservation and the genetics of populations. 2d ed. Oxford: Wiley-Blackwell.

  This textbook introduces population genetics concepts and methodologies in an applied context, considering the importance of these applications toward understanding the ecology of species in natural populations, and in support of effective strategies for species conservation.

• Gillespie, John H. 2004. Population genetics: A concise guide. Baltimore: Johns Hopkins Univ. Press.

  This is a brief introduction to the subject, based on short courses given by the author on those aspects of population genetics he sees as central and essential. It is a clear and concise introduction that students find quite accessible.

• Hartl, Daniel L., and Andrew G. Clark. 2007. Principles of population genetics. 4th ed. Sunderland, MA: Sinauer.

  This book grew out of the initial edition (from 1980, authored by Hartl on his own) into one of two key texts on the subject (the other being Hedrick 2010). It provides good balance between empirical and theoretical approaches to the field, and is up to date with modern methodologies.

• Hedrick, Philip W. 2010. Genetics of populations. 4th ed. Boston: Jones & Bartlett.

  The first edition of the text was published in 1983. This book is good about explaining relevant mathematical concepts clearly and from first principles, and the latest edition is up to date with respect to the most recent empirical data.

• Provine, William B. 2001. The origins of theoretical population genetics. 2d rev. ed. Chicago: Univ. of Chicago Press.

  This book traces the origins of population genetics from the initial ideas of Darwin through the rediscovery of Mendel’s ideas and the period of conflict between “Mendelians” and “biometricians.” It finishes with a review of the major contributors in the 20th century.