Behavioral genetics is the field of study that examines the role of genetics in animal (including human) behavior. Often associated with the "nature versus nurture" debate, behavioral genetics is highly interdisciplinary, involving contributions from biology, genetics, epigenetics, ethology, psychology, and statistics. Behavioral geneticists study the inheritance of behavioral traits. In humans, this information is often gathered through the use of the twin study or adoption study. In animal studies, breeding, transgenesis, and gene knockout techniques are common. Psychiatric genetics is a closely related field.
Sir Francis Galton, a nineteenth-century intellectual, is recognized as one of the first behavioral geneticists. Galton, a cousin of Charles Darwin, studied the heritability of human ability, focusing on mental characteristics as well as eminence among close relatives in the English upper class. In 1869, Galton published his results in Hereditary Genius.[1] In his work, Galton "introduced multivariate analysis and paved the way towards modern Bayesian statistics" that are used throughout the sciences—launching what has been dubbed the "Statistical Enlightenment".[2] Galton is often credited as the pioneer of eugenics. Subsequently, Adolf Hitler is believed to have been motivated by Galton's work in enacting the Final Solution during World War II.[3]
In 1951, Calvin S. Hall in his seminal book chapter on behavioral genetics introduced the term "psychogenetic",[4] which enjoyed some limited popularity in the 1960s and 1970s.[5][6] However, it eventually disappeared from usage in favor of "behavior genetics".
Behavior genetics, per-se, gained recognition as a research discipline with the publication in 1960 of the textbook Behavior Genetics by J.L. Fuller and W.R. Thompson.[7] Nowadays, it is widely accepted that most behaviors in animals and humans are under some degree of genetic influence.[8]
Underscoring the role of evolution in behavioral genetics, Theodosius Dobzhansky was elected the first president of the Behavior Genetics Association in 1972; the BGA bestows the Dobzhansky Award on researchers for their outstanding contributions to the field. In the early 1970s, Lee Ehrman, a doctoral student of Dobzhansky, wrote seminal papers describing the relationship between genotype frequency and mating success in Drosophila,[9][10][11] lending impetus to the pursuit of genetic studies of behaviour in other animals. Studies on hygienic behavior in honeybees were also carried out early in the history of the field.[12][13] The social behavior of honey bees has also been studied and recent work has focused on the gene involved in the foraging behavior of Drosophila; this essentially allowed for deriving a relationship between gene expression and behavior, where the gene regulating foraging behavior in Drosophila also regulated social behavior in bees.[14]
The primary goal of behavioral genetics is to establish causal relationships between genes and behavior.[3] One common approach is the reductionist approach. Under this approach, scientists first observe a psychological or behavioral function (e.g., schizophrenia). Next, using known functions of brain systems and neurotransmitter systems, scientists correlate behavior to these brain areas (e.g., excess glutamate release may stimulate excess dopamine in the limbic system leading to schizophrenic symptoms). Once scientists are able to map behavior to biological systems, they can then turn to genetics to understand the development of these biological systems (e.g., an abnormal glutamate gene could be a candidate gene for schizophrenia). Quantitative trait loci (QTL) are the attempt to map genes to behavior. Other methods involve twin studies and adoption studies. These two methods attempt to separate environmental contributions to behavior from genetic contributions.
The Human Genome Project has allowed scientists to understand the coding sequence of human DNA nucleotides. Once candidate genes for behaviors are discovered scientists may be able to genetically screen individuals to determine their likelihood of developing certain pathologies.
Notable behavioral geneticists
Notable behavioral geneticists include Dorret Boomsma, Wim Crusio (the founding editor of the journal Genes, Brain and Behavior), John DeFries, Lindon Eaves, David Fulker, John Hewitt, Kenneth Kendler, John Loehlin, Nick Martin, Gerald McClearn, Robert Plomin, Theodore Reich (a pioneer in psychiatric genetics), Hans van Abeelen, Avshalom Caspi, Steven G. Vandenberg (the founding editor of the journal Behavior Genetics), and Irving Gottesman.
Behavioral geneticists are active in a variety of scientific disciplines including biology, medicine, pharmacology, psychiatry, and psychology; thus, behavioral-genetic research is published in a variety of scientific journals, including Nature and Science. Journals that specifically publish research in behavioral genetics include Behavior Genetics, Molecular Psychiatry, Psychiatric Genetics, Twin Research and Human Genetics, Genes, Brain and Behavior, and the Journal of Neurogenetics.
