Topic 3 - Genetics & Psychopathology

Question 1

What is behavioural genetics?

Answer 1

Behavioural genetics is the study of how genetics and the environment influence behaviour.

Question 2

What is the goal of behavioural genetics?

Answer 2

The goal/effort of behavioural genetics is to establish causal link between genes and behaviour (/neural mechanisms)

Question 3

What are five methods employed in behavioural genetics?

Answer 3

Twin studies, molecular genetics, quantitative trait mapping, transgenic studies, knockout studies.

Question 4

What does epidemiology mean?

Answer 4

It refers to how often a disease occurs in a population and why.

Question 5

What are concordance rates (CRs)?

Answer 5

CRs are a measure of probability - if one twin has X, what is the probability of the other twin having X?

Question 6

What did Bouchard et al. (1990) (Minnesota Twin Study) find?

Answer 6

They found that 70% variance in IQ between twins was associated with genetic variation.

Question 7

What are the advantages of twin studies?

Answer 7

1. Allow measurements of gene vs environment.
2. Higher statistical power by reducing genetic and environmental variability.

Question 8

What are the limitations of twin studies?

Answer 8

1. Lack of randomisation.
2. Genetic factors might underlie twin births.
3. Does not allow to test for gene x environment interaction.

Question 9

What does the field of molecular genetics investigate?

Answer 9

Structure of the DNA, its cells’ activity and its influence on the overall makeup of an organism.

Question 10

What are genes?

Answer 10

Genes are the functional units of the DNA. They are stretches of the DNA which code for polypeptides, to make protein.

Question 11

What are two types of genetic variations?

Answer 11

Polymorphisms and mutations.

Question 12

What are polymorphisms?

Answer 12

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.

Question 13

What does SNPs stand for?

Answer 13

Single Nucleotide Polymorphisms.

Question 14

What are SNPs?

Answer 14

Single Nucleotide Polymorphisms are a class of polymorphisms that involve a single base change.

Question 15

With what percentage do SNPs affect phenotype?

Answer 15

3-5%.

Question 16

What is the genotype?

Answer 16

The genotype is the genetic code of the individual.

Question 17

What is the phenotype?

Answer 17

The phenotype is the expression of the genotypes (traits).

Question 18

What are indels?

Answer 18

Small insertions/deletions. They are a type of polymorphism.

Question 19

What do indels do?

Answer 19

They insert or delete a base in the genome.

Question 20

What does CNPs stand for?

Answer 20

Large-scale copy number polymorphism.

Question 21

What are CNPs?

Answer 21

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.

Question 22

What are mutations?

Answer 22

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.

Question 23

What would be a beneficial mutation?

Answer 23

The sickle cell anemia.

Question 24

What is quantitative trait mapping?

Answer 24

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.

Question 25

Why is it difficult to study variations in traits?

Answer 25

Because traits might be controlled by lots of genes, each with varying effects on the trait.

Question 26

What do transgenic studies do? Example?

Answer 26

They insert a new gene into the genome. Example: mice studies that make them glow in the dark.

Question 27

What are knockout studies?

Answer 27

They are studies where a gene is deactivated. They are use to study the function of specific genes and they used stem cells.

Question 28

What are two examples of knockout studies?

Answer 28

Mice and the FOXP2 gene, related to linguistic ability and relevant for schizophrenia + Study using CRISPR involving mosquitos and malaria.

Question 29

What is the gene DRD4 related to?

Answer 29

Sensation seeking.

Question 30

Why are knockout studies useful?

Answer 30

To identify genes that are related with behaviours/diseases to then inform treatment.