GEI
rGE=..
types
gene-environment correlation= when there are genetically influenced differences in exposure to environmental risk factors.
passive, active, evocative.
PASSIVE.
EVOCATIVE.
ACTIVE.
- children receive genotypes correlated with the family environment.
- genetic propensities make people behave in some ways, and these behaviors elicit specific reactions in others.
- individuals seek/create environments correlated with genetic predispositions.
GE Interaction VS GE Correlation
1. different genotypes respond differently to environments.
2. different genotypes are exposed to different environments.
Passive rGE 2 models
- double advantage: parents with genetic predisposition for educational attainment -> good learning environment at home.
- double disadvantage: parents with predisposition for depression-> negative environment at home.
METHODS for PASSIVE rGE
1. compare correlations between environmental measures and traits, in adoptive and nonadoptive families.
2. children of twins (COT): pseudo-adoption design, examines whether measures of the family environment have a direct effect on child outcomes or are genetically mediated.
3. extended children of twins: combines COT and a comparable sample of twins.
METHODS FOR ENACTIVE rGE
adopted children with high genetic risk fo psychopathology evoke different environment than children with a low risk.
METHODS for ACTIVE rGE
1. check if MZ twins are more in the same environment than DZ twins.
2.correlations between families' environment assessing the other two types of rGE.
GxE INTERACTION definition.
models
the effect of the genotype on a phenotype depends on the environment.
diathesis-stress model.
vantage sensitivity.
differentia suceptibility framework.
diathesis stress model
individuals with specific risk to a disorder are sensitive to the effects of risky environments.
vantage sensitivity
individuals gaining more than others from a good environment because of being more sensitive.
differential suceptibility framework
individuals are sensitive both to negative as well as positive influences because of plasticity genes.
GxE studies on plants/animals
randomized controlled experiments.
GxE human research
looks at children with all their genes and how they gwo changing environments.
higher SES- higher heritability. low SES-low heritability.
GxE models
1. transactional model: being smart makes u smart, as you seek more challenging tasks, environments.
2. Scarr-Rowe hypothesis: high SES enables genetic potential to unfold and enlarges differences between individuals with higher/lower genetic predispositions.
3. Compensatory advantage H: low genetic endowments have less impact on education for children from high SES families.
missing heritability
the gap between heritability hestimates from twin/family studies and that captured by polygenic signals from GWAS.
candidate genes and dark era
idea that the correlation between a gene and a phenotype differs in different environments.
WRONG! individual genes rarely replicate and thos that do account for less than 0.1% of variance.
dark era: 2 decades, of doing this type of research.
endophenotypes
quantitative biological trait that is reliable in relfecting the function of a biological system, is heritable, and much more related to the root causes of the disease.
BMI.
GenomeEUtwin project
body mass index, weight/height^2.
healthy: 18.5-24.9.
found BMI is 70% heritable, but environment is important too.
heritability of eating behavior and weight
after 1 year, remains stable and high, while C disappears.
zero at birth and first months of life, environment is more important.
leptin hormone-mouse-humans-obesity
mices producing less leptin-> constant appetite-> obesity. give them leptin, reduced appetite. leptine-hunger-appetite.
in humans: does not work, because we don't have deficiency of leptin. leptin level is heritable. obesity is caused by GxE.
obesity epidemic
no genetic cause: gene frequencies do not change that quickly. environmental causes.
finnish study: educational level-BMI
parent's educational level influences BMI.
in low-education families, C is more important.
in high-education families, A dominates.
Personality.
Big 5
stable pattern of behavior, thoughts, motive, and emotions.
extraversion, conscientiousness, opennes to experience, neuroticism, agreeableness.
high genetic influence (40-60%) and low environment impact.
consistency of personality.
genetic explanation
prettu stable over life span.
neuroticism high-young adults, low-old people.
consientiousness vice versa.
early life: stability is 100% explained by genetic. then in late adulthood is just above 50%, and the rest is E.
heritability of personality decreases with age.
well-being, sexual orientation heritability
small heritable component.
is partly heritable (35%), but it's not determined. can be a gradual choice.
religion and politics heritability
R: there is a genetic component but C plays a bigger role, as well as individual differences in the degree of religiousness.
P: there is heritability, through personality traits.
cognitive abilities
individual differences in reasoning and memory, very stable, predictors of social, educational, occupational outcomes.
current definitions of intelligence: APA, Sternberg, Gottfredson
- APA: understand complex ideas, adapt to environment, learn from experience, reasoning.
-Sternberg: problem-solving & communicate solutions
-Gottfredson: determines academic, career, social success.
Revn's Progressive Matrices
culturally-independent test for IQ. only sequences of shapes to complete.
Cattel-Horn-Carroll Theory.
Positive Manifold
there is a general factor (g) of intelligence, under which all other cognitive abilities develop from boraders to narrowers. they all correlate, indicating a latent dimension (g).
Causes of variation in Intelligence
heritability of 50%.
- Education: for every additional year, rise of 1-5 points in IQ.
- Immigration and Adoption: average increase of +17.6 IQ points in adopted children compared to 'left behind' children (higher SES, opportunities, care).
the Flynn Effect
IQ increases by 3 points every decade in developing countires; in industriablized-stable countires tends to slow down or stop. mostlry explained by environmental factors.
interpretation of Flynn Effect
increase in abstract reasoning: ignore appereances and reckon formal categories.
"The myth of meritocracy"
meritocracy leads to inequality of opportunity and reward based on genetic differences.
genetic research to improve psychology and society
- control/detect real harms/benefits.
- personalized interventions.
polygenic predictors for risk of diseases, treatment interactions. Be careful!
- genetic editing and embryo selection procedures.
Eugenics (Galton).
improve humans through selective breeding of the good stock.
good: improve the good stock, tax incentives.
bad: eliminate the bad stock, mandatory sterilization.
eugenics in history.
biggest issues
Britain: tax incentives based on parents' IQs.
USA: sterilization laws based on IQ, institutionalization, criminal history.
Sweden: sterilization based on low IQ.
Germany: sterilization and genocide based on inferiority.
- decisions based on biological race.
- made top-down by authoritarian governments.
The Gloomy Prospect (Plomin)
the shared environment effects are down to chance. the DNA causes the stable. long-lasting, predictable outcomes.
Turkheimer's view
individual phenotypic space not determined by genes nor environment defines the boundaries in which free will gets to play.