Nature-Nurture: family and genetic influences Flashcards
Across how old is there genetic contribution to LADs?
2-16 and presumably into
adulthood
True or False?
Genetic influences are not static: heritability of LADs increases during the development
True
True or False?
FOXP2 gene has been discovered (KE family) and is the only gene causing language development
False - many other genes play the role in language development
Name the three types of interplay
Epigenetics = E -> G (environment influence genome)
Gene-Environment Correlation = G -> E (gene modifies environment)
Gene-Environment Interaction = G x E (genetic + environmental to put people at risk to developmental-specific traits)
They do not act independently from each other
Describe what is genetics
Genetic material (DNA) is passed on from parents to offspring (vertical genetic transfer)
Human genome = It’s a molecule of DNA. 3 billion nucleotide base pairs.
There are 20-25,000 genes in the human genome
More than 99% of the DNA sequence = same ~ 1% of the DNA sequence is variable (the source of individual differences)
What is gene expression?
When DNA sequence of a gene is converted
into functional protein structures.
Gene expression changes to produce different proteins.
How much + duration of proteins are made = can vary
What is the difference between genetics and epigenetics?
Genetics (i.e., DNA sequence) = what specific proteins are synthesised.
Epigenetics = how much of the proteins is made, and where + when it is synthesised
What is DNA methylation?
Methyl groups attach to DNA compacting it + preventing its code from being read/ made into proteins
This is a well studied example of epigenetics.
What is epigenetic modulation?
Kanherkar et al. (2014) = identified many environmental effects on genetics
Psychological state
Social interaction
Diet
Disease exposure
Exercise
Financial Status
Drug abuse
Alternative meds
therapeutic drugs
Seasonal correlations
Toxic/ chemicals
Microbiome
What happened in Weaver et al. (2004) study?
High-nurturing mothers = low anxious offspring vs Low-nurturing mothers raise = high anxious offspring Nurturing bhvr of a mother rat = pups’ epigenomes.
In low-nurturing offspring = glucocorticoid receptor gene (Nr3c1) = off + leads to higher level of stress and anxiety.
Epigenetic pattern that mum causes = lasts even after the pups become adults.
Describe the gene-environment correlation.
The environment is not independent of the person: humans select, modify and create environments in line with their genetic propensities.
When individuals with a genetic propensity for a trait are in environments, choose or create the environments, that support expression of the trait
What are the three types of GE correlation?
Passive
Evocative
Active:
What is Passive GE correlation?
Parental genes influence parental behaviours = a role in determining the kind of parenting style they give.
Source = parents and siblings.
Example:
Children with genetic vulnerability to antisocial behaviour is exposed to family maltreatment
What is Evocative GE correlation?
Child genes influence child behaviours = a role in eliciting different types of responses in other people
Source = anybody
Example:
Children with positive personality (high extraversion) evoke more
positive responses from parents/peers
O’connor et al. (1998) = studied adoptive families, children were measured @ 7,9,10,11 and 12. They identified non-risk + at risk for anti-social bhvr in children and measured against mean level of neg. control. Children at risk = had higher level of neg. despite the environment. Their bhvr elicited neg. response from their carers.
What is Active GE correlation?
Child genes influence child behaviours= a role in determining how children shape + select their environments. A “rich get richer’ effect.
Examples:
Athletic individual seeks out athletic endeavours
Antisocial person seeks out antisocial peers
Describe GE across development
important for changes in development
Influence of passive GE = declines from infancy to adolescence, but importance of the active GE increases throughout period
Identified = the extent of how an experience is influenced by individual’s genetic factors increases with development
2 possible mechanisms:
New genes = important (genetic innovation)
individuals select their own experiences (genetic amplification)
Describe gene-environment interaction
Genetically influenced sensitivity to specific environment
In this case, genetic influences on a trait depend on the
environment
Specific environments and genetic susceptibilities to these
environments predict a trait
Example:
Jaffee et al. (2005) = A twin study. Twin 1 = genetic marker, Twin 2 = included in study. Child conduct problems as a function of genetic risk and physical maltreatment. Children with the highest genetic risk, were the most abused.
Pleuss and Belsky (2011) = proposed two models = Diathesis-stress and differential susceptibility model. Suggested both environment + genetic factors were important
Diathesis-stress = high risk for neg. environment. Resilient indvdls = genetically won’t experience neg. outcome.
What is a limitation of studies looking at the gene-environment interaction?
Studies focus on neg. environments + development of neg. traits e.g conduct problems
We don’t understand the outcomes of pos. environments
