L1: Origins of Development Flashcards
Describe G x E Theory
LG1
- Model by Scarr & McCartney
- Genes drive experiences because people are motivated to (self) select an environment that is best suited to our genotype
- Genes and environment have a mutual influence on each other. Our genotype influences the type of environment we select, and our phenotype influences how we interact with that environment.
G x E effects can be passive, evocative, or active.
* Passive effects refer to parents providing both genes and an environment that supports these genes.
* Evocative effects refer to a child’s genetically influences characteristics eliciting particular responses from others in their environment.
* Active effects refer to an individual actively seeking an environment that is suited to their genotype.
Both genes and environment can have a limiting effect on each other
* G limiting E = Breastfeeding x IQ. Fatty acids in breast milk are super good for brain development, but the proteins which process these fatty acids are controlled by genes
* E limiting G = SES x IQ. Heritability of IQ is less in children with low SES because they have less opportunity to choose their environment, therefore making their genotypic differences less pronounced.
Define genotype
The genetic makeup of an organism, encoded as alleles in DNA
Define alleles
- All variations of a gene that exist at a specific location on a given chromosome
- Can be codominant, dominant, or recessive
Define phenotype
The ways that the genetic information of is expressed within an organism
Define genes
inherited instructons for producing proteins
What are constraints to development?
1) Vitality
* Certain processes/structures must be completed in order for next steps in development to take place
2) Differentiation
* Canalization: process by which cells become commited to differentiating into a particular type/structure
* Epigenetic regulation: changes in an organisms phenotype due to specific cell types becoming (de)activated in response to the surrounding chemical environment
* Methylation: turning off activity of a gene by attaching methyl groups to base pairs in DNA sequence. Study showed that feeding male rats low-protein diets resulted in gene regulated metabolic changes in their offspring.
3) Timing & Sequencing
* Some structures / processes can proceed independently, others must be completed sequentially
* Heterochronic genes dictate sequential development through activating specific genes only at certain times in development
Describe methylation
Process of turning off activity of certain genes by attaching methyl groups to specific DNA base pairings.
Methylation x Diet Study
* Method - male rats either in low-protein diet or control diet groups. All male rates mated with females who were on the control diet. The genetic makeup of their offspring was examined
* Results - there was evidence of gene regulated metabolic changes in the offpsring of the low-diet male mice
Describe gene sequencing
Base pairs consist of two main sequences:
2) Structural Sequence
* Codes for the assembly of proteins that give rise to traits & structures (EX: enzymes)
1) Regulatory Sequence
* Codes for (de)activation of genes
* Most genes are regulatory
Describe G x E Effects
LG1
G x E effects can be passive, evocative, or active.
* Passive effects refer to parents providing both genes and an environment that supports these genes.
* Evocative effects refer to a child’s genetically influences characteristics eliciting particular responses from others in their environment.
* Active effects refer to an individual actively seeking an environment that is suited to their genotype.
Provide examples for how the environment influences brain development
LG1
Deprived Environment:
* Compensation plasticity: capacity of brain areas that have been deprived of its normal input/processing abilities to start performing an alternative function.
* The brain area can either help compensate for the loss or increase the capacities of remaining functions.
Enriched Environment:
* Experience dependent plasticity: ability of brain to physicall change as a result of experience
* Tends to occur w skill acquisition (EX: Dragonski juggling tings)
Provide an example of a G x E interaction that occurs during puberty
LG1
- Environment - teenagers are more likely to engage in risky behaviour in group settings
- Genes - the emotional arousal (limbic) system is more activated in social settings
- When in social situations, the emotional arousal (limbic) system becomes activated and overrides the cognitive control (PFC) system, making people more prone to pursuing risky immediate rewards.
- With age these systems become better integrated and therefore there is less risk taking behaviour.
