GENE-ENVIRONMENT INTERPLAY PART II

Flashcards covering key concepts from the 'Gene-Environment Interplay Part II' lecture, including Diathesis Stress vs. Differential Susceptibility, Barnes & Beaver (2012) study on marriage and desistance, epigenetics, and Beaver et al. (2008, 2012) studies on peers and parenting.

According to the Diathesis Stress model, what increases the likelihood of exhibiting antisocial phenotypes?

Having more at-risk genes and at-risk environments.

How does the Differential Susceptibility model explain the impact of genes and environments?

Genes determine an individual's susceptibility to being impacted by different environments, with resource-rich environments allowing for greatest genetic expression and negative environments allowing for greatest environmental influence.

What do traditional criminologists believe about the effect of marriage on criminal behavior?

They believe that marriage inhibits criminal behavior by increasing perceived costs of crime and potential loss for the offender.

What was Dr. Barnes' core hypothesis regarding the effect of marriage on desistance from crime in his (2012) paper?

He hypothesized that an active gene-environment correlation (rGE) is present, where genetic factors influence both the likelihood of marriage and desistance.

What is an active gene-environment correlation (rGE)?

It is when genetic factors influence the environments individuals select into or create for themselves.

Why did Barnes (2012) include biologically related siblings, twins, half-siblings, and cousins in the Add Health sample?

To calculate heritability estimates for marriage and desistance outcomes.

In Barnes' (2012) study, what percentage of the variance in marriage outcomes was accounted for by genetic factors?

Genetic factors accounted for 56% of the variance in marriage outcomes.

In Barnes' (2012) study, what percentage of the variance in desistance outcomes was accounted for by genetic factors?

Genetic factors accounted for 49% of the variance in desistance outcomes.

What did Barnes (2012) conclude about the influence of genetic factors on marriage and desistance?

Genetic factors influence personality development, which influences the propensity to marry, and it is likely that the same genes influencing marriage also influence desistance, indicating an active rGE.

What was the implication of Barnes' finding that the effect of marriage on desistance was weaker after including genetic influences in the model?

It suggests that studies that do not account for genetic influences are likely overestimating the environmental effect of marriage on desistance.

What is epigenetics?

Epigenetics refers to changes in gene function that do not involve altering the DNA sequence, where natural and environmental factors can 'switch' genes on and off.

Why does epigenetics sometimes have a negative connotation?

It is commonly confused with eugenics and the idea of changing DNA sequences to create 'designer babies' or 'super soldiers,' rather than its true nature as a natural process of gene regulation.

How do all cells in the human body, except red blood cells, specialize to perform different functions despite having the exact same DNA?

Through epigenetics, which involves processes that turn specific genes on or off to specialize cells like heart, skin, or liver cells.

What is the epigenome?

The epigenome refers to chemical markers along DNA strands that act as gate-keepers to genes, turning gene activity on or off.

How does DNA methylation affect gene activity?

DNA methylation turns off a gene by attaching a methyl group to a cytosine nucleotide in the promotor region, blocking RNA from transcribing the gene.

How does histone acetylation affect gene activity?

Histone acetylation turns on a gene by attaching an acetyl group to a histone, which loosens tightly spooled DNA, allowing RNA to access genes for transcription.

What did the rat pup example on histone acetylation demonstrate about environmental influence on gene expression?

Attentive mother rats (licking their pups) turned on the GR gene, helping pups deal with stress and leading to confident adults, while unlicked pups grew up to be anxious, demonstrating how environment can turn genes on or off.

What are stem cells, and how do they relate to epigenetics?

Stem cells are undifferentiated cells capable of replicating and differentiating into specialized cells. They have not yet undergone epigenetic processes to become specialized, which is how epigenetics transforms them.

Why is epigenetics considered a form of gene-environment interplay?

Because while it does not change DNA sequences, the environment influences epigenetic processes, which in turn influence the manifestation of different phenotypes or traits.

How does the study by Beaver et al. (2008) approach delinquent peer formation?

It approaches delinquent peer formation from a gene-environment correlation (rGE) perspective, looking at what influences individuals to select into deviant peer groups.

According to Gottfredson and Hirschi's control theory, why do some youths select into antisocial peer networks?

They hypothesize that crime-producing traits can differentially lead some youths to select themselves into antisocial peer networks, though they would not agree these traits are genetically influenced.

What specific gene was assessed in Beaver et al.'s (2008) study on delinquent peer formation, and what was hypothesized?

The 10R allele of the DAT1 gene was assessed, and it was hypothesized that phenotypes associated with this allele (like ADHD, externalizing behavior) would align with selecting into deviant peer groups.

What was the strongest predictor of associating with delinquent peers in Beaver et al.'s (2008) study?

Age was the strongest predictor, with association with delinquent peers increasing as age increased, due to both biological influences (puberty) and different environmental opportunities.

What specific finding regarding the DAT1 gene and delinquent peer association was observed by Beaver et al. (2008)?

The 10R allele of the DAT1 gene was predictive of having antisocial friends, but only for males, particularly those with the greatest number of risk alleles.

What combined influence was suggested by the finding that the DAT1 allele only affected delinquent peer formation for males in at-risk family environments?

It suggested a simultaneous gene-environment interaction (GxE) and gene-environment correlation (rGE), where an at-risk genotype and at-risk family environment jointly influence peer group selection and subsequent outcomes.

What did Plomin et al. (1994) find about the heritability of family measures in behavioral genetic research on parenting?

They found that 15 out of 18 family measures were influenced by genetic factors, with about 26% of the variance attributable to genetic factors, indicating that parenting is not purely environmental.

In Beaver et al.'s (2012) study on gene influences on parental negativity and childhood maltreatment, which genes were associated with parenting variations for white males only?

DRD2 and DAT1 were associated with variations in parenting for white males only, while DRD4 was not related to any variation.

Why could Beaver et al.'s (2012) study not differentiate the specific type of gene-environment correlation (rGE) present for parenting outcomes?

The study design did not allow differentiation between evocative rGE (children eliciting responses) or passive rGE (parents passing down genes and environment), though it suggested a combination of both.