Lecture 14: Behavioural Genetics Flashcards
(10 cards)
***How can heritability estimates be calculated from twin studies?
- Monozygotic twins raised together
- Dizygotic twins raised together
- monozygotic twins raised apart
- adopted siblings
Ratio of Phenotype variance/Genetic variance
***What is a quantitative genetic analysis of
behaviour?
- characterize quantitatively a behavioural phenotype in a given population/strain derived from nature or by artificial selection
- Examining the changes in phenotype in sets of progeny from test crosses between different populations
- infer statistically the number of genes responsible and their interactions
***What are single gene studies of behaviour?
Testing hypothesised genes from quantitative analysis.
=> Studying the contribution of likely candidates for a phenotype based on what is known about their neurobiological bases
– Alcohol dehydrogenase for alcoholism
***What are the problems in explaining behaviour with genetics?
- lack of evidence for any complex psychological trait that is determined by a single gene
- meaning of genetic marker
vagueness in incorporating a mechanistic role for the gene in the phenotype - a definitional problem with behaviour
The measurable expression of a trait is the
phentotype
what is the Phenotypic variance formula?
(Vp) = Vg + Ve + Vge
note:
Vg = Genetic variance
Ve = Environmental variance
Vge = Gene-Environment interac4ons
_____________ is the component of the variance
of the phenotype that can be explained by
heritable factors
heritability
what is the formula of heritability quotient of a trait?
h2 = V(g) / V(p)
problems with quantitative analysis
- Results do not identify individual genes
- Necessity for large pedigrees & crossmating
makes human studies unlikely
problems with single gene analysis
- Ignores the important contribution of
background genotype to phenotype - Redundancy and pleiotropy in mechanisms
- Ignores roles for adapta4on and
developmental effects