Topic 3 - Genetics & Psychopathology Flashcards
What is behavioural genetics?
Behavioural genetics is the study of how genetics and the environment influence behaviour.
What is the goal of behavioural genetics?
The goal/effort of behavioural genetics is to establish causal link between genes and behaviour (/neural mechanisms)
What are five methods employed in behavioural genetics?
Twin studies, molecular genetics, quantitative trait mapping, transgenic studies, knockout studies.
What does epidemiology mean?
It refers to how often a disease occurs in a population and why.
What are concordance rates (CRs)?
CRs are a measure of probability - if one twin has X, what is the probability of the other twin having X?
What did Bouchard et al. (1990) (Minnesota Twin Study) find?
They found that 70% variance in IQ between twins was associated with genetic variation.
What are the advantages of twin studies?
- Allow measurements of gene vs environment.
- Higher statistical power by reducing genetic and environmental variability.
What are the limitations of twin studies?
- Lack of randomisation.
- Genetic factors might underlie twin births.
- Does not allow to test for gene x environment interaction.
What does the field of molecular genetics investigate?
Structure of the DNA, its cells’ activity and its influence on the overall makeup of an organism.
What are genes?
Genes are the functional units of the DNA. They are stretches of the DNA which code for polypeptides, to make protein.
What are two types of genetic variations?
Polymorphisms and mutations.
What are polymorphisms?
Polymorphisms are common (>1%) genetic variations. They do equal disease but they might contribute to predisposition, progression and response to treatment. They might be inherited or arise the novo.
What does SNPs stand for?
Single Nucleotide Polymorphisms.
What are SNPs?
Single Nucleotide Polymorphisms are a class of polymorphisms that involve a single base change.
With what percentage do SNPs affect phenotype?
3-5%.
What is the genotype?
The genotype is the genetic code of the individual.
What is the phenotype?
The phenotype is the expression of the genotypes (traits).
What are indels?
Small insertions/deletions. They are a type of polymorphism.
What do indels do?
They insert or delete a base in the genome.
What does CNPs stand for?
Large-scale copy number polymorphism.
What are CNPs?
They are variations in the number of copies in a DNA region. They might arise for indels. They can involve loss of one or both copies of a DNA segment, or the presence of more than two copies.
What are mutations?
Mutations are rare (<1%) changes in the DNA. They can cause a change in the resulting protein, the impairment/inhibition of the gene, or they can leave both unaffected. They are mostly equal with disease, although some can be beneficial.
What would be a beneficial mutation?
The sickle cell anemia.
What is quantitative trait mapping?
QTM is a technique used to study the DNA. It is mostly concerned with Quantitative Trait Locus (QTL): the effort to localise a the stretch of the DNA related to a specific trait.
Why is it difficult to study variations in traits?
Because traits might be controlled by lots of genes, each with varying effects on the trait.
What do transgenic studies do? Example?
They insert a new gene into the genome. Example: mice studies that make them glow in the dark.
What are knockout studies?
They are studies where a gene is deactivated. They are use to study the function of specific genes and they used stem cells.
What are two examples of knockout studies?
Mice and the FOXP2 gene, related to linguistic ability and relevant for schizophrenia + Study using CRISPR involving mosquitos and malaria.
What is the gene DRD4 related to?
Sensation seeking.
Why are knockout studies useful?
To identify genes that are related with behaviours/diseases to then inform treatment.
