Behavioral genetics Flashcards
Define “behavioral genetics”
Behavioral genetics is the field of study that examines the role of genetics in animal (including human) behavior
Which prominent intellectual is seen as one of the first behavioral geneticists?
Sir Francis Galton
Who wrote “Hereditary Genius”?
Sir Francis Galton, in 1869
When did Francis Galton publish “Hereditary Genius”?
1869
Who introduced the term “psychogenetics”?
Calvin S. Hall
Where was the term “psychogenetics” first used?
In Calvin S. Hall’s seminal book chapter on behavioral genetics, from 1951
When did “behavioral genetics” gain recognition as a research discipline?
Behavior genetics gained recognition as a research discipline with the publication in 1960 of the textbook Behavior Genetics by J.L. Fuller and W.R. Thompson
Who wrote the textbook Behavior Genetics in 1960?
J.L. Fuller and W.R. Thompson
What was the focus of Lee Ehrman’s seminal paper in the early 1970’s?
The relationship between genotype frequency and mating success in Drosophila
Who wrote a seminal paper on the relationship between genotype frequency and mating success in Drosophila?
Lee Ehrman, in the early 1970’s
What is “The primary goal of behavioral genetics”?
The primary goal of behavioral genetics is to establish causal relationships between genes and behavior
How is a reductionist approach used in behavioral genetics (with schizophrenia as an example)?
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).
Apart from the reductionist method, which methods are often used in behavioral genetics?
Other methods used with human populations involve twin studies and adoption studies. With non-human animals, selection experiments have often been employed.
What is a quantitative trait locus
Quantitative trait loci (QTLs) are stretches of DNA containing or linked to the genes that underlie a quantitative trait. Mapping regions of the genome that contain genes involved in specifying a quantitative trait is done using molecular tags such as AFLP or, more commonly SNPs.
What is polygenic inheritance?
Polygenic inheritance refers to inheritance of a phenotypic characteristic (trait) that is attributable to two or more genes and can be measured quantitatively. The assumption of polygenic inheritance is that all involved loci make an equal contribution to the symptoms of the disease
What is multifactorial inheritance
Multifactorial inheritance refers to polygenic inheritance that also includes interactions with the environment
How does polygenic inheritance differ from Mendelian (monogenetic) inheritance?
Unlike monogenic traits, polygenic traits do not follow patterns of Mendelian inheritance (separated traits). Instead, their phenotypes typically vary along a continuous gradient depicted by a bell curve.
How can the distribution of phenotypes from n number of interacting genotypes be calculated?
Polygenic inheritance can be explained as Mendelian inheritance at many loci,[6] resulting in a trait which is normally-distributed. If n is the number of involved loci, then the coefficients of the binomial expansion of (a + b)2n will give the frequency of distribution of all n allele combinations. For a sufficiently high n, this binomial distribution will begin to resemble a normal distribution.
How is a disease state typically defined for polygenetic traits?
The disease state will become apparent at one of the tails of the distribution, past some threshold value. Disease states of increasing severity will be expected the further one goes past the threshold and away from the mean.
Give an example of how polygenetic inheritance can be an insufficient explanation for some diseases.
Turnpenny (2004) discusses how simple polygenic inheritance cannot explain some diseases such as the onset of Type I diabetes mellitus, and that in cases such as these, not all genes are thought to make an equal contribution. In other words, the assumption of normally distributed phenotypes does not hold up.
Name one basic assumption of polygenic inheritance
The assumption of polygenic inheritance is that all involved loci make an equal contribution to the symptoms of the disease. This should result in a normal curve distribution of genotypes. When it does not, the idea of polygenetic inheritance cannot be supported for that illness.
