Lecture 1 : Introduction to Behavioural Genetics

Question 1

many traits are heritable…

Answer 1

personality, intelligence, ideology and religiosity

Question 2

Heritability for inheriting certain disorders:

• bipolar
• schizophrenia
• AD
• MDD
• generalized anxiety disorder

Answer 2

BPD - 0.85
SZ - 0.8
AD - 0.75 
MDD - 0.4
GAD - 0.3

Question 3

Behaviour

Answer 3

overt actions (like running studying etc) and mental processes (emotions)

Question 4

The greater the similarity in terms of genes (allelic similarity)

Answer 4

the greater the expected similarity in behaviour

Question 5

Trait correlations between identical twins

Answer 5

generally moderate (r> 0.5) but never perfect (r<1.0) because of environmental effects

• same genes, different activity
• same genes, different brain (too complex to be genetically preprogrammed)

Question 6

Variability of phenotype is due to…

Answer 6

variability due to environmental effects + variability due to genes

Question 7

Genes affect our access and attraction…

Answer 7

…to environments, our susceptibility to the environment

Question 8

Monoamine oxidase A (MAOA)

Answer 8

gene variant of which affects vulnerability to childhood maltreatment causing aggressiveness

Question 9

natural selection

Answer 9

a superior organism is more likely to survive and reproduce than an inferior conspecific (traits that confer a survival advantage are more likely to be passed along to next gen

Question 10

Francis Galton

Answer 10

father of behavioural genetics

• argued that behavioural traits were heritable
• accidentally inspired eugenics

Question 11

Human Genome Project

Answer 11

dedicated to identifying and mapping the genes within the human genome

• ran from 1990-2003 and cost $2.7 billion
• 20,000 - 25,000 genes identified (much less than expected)

Question 12

Trypsin-giemsa staining

Answer 12

reveals a band pattern (physical address for a gene)

Question 13

How much DNA in a cell

Answer 13

• 3 billion bps in human genome
• 23 chromosome pairs so 46 total
• nucleus has 2 meters of DNA

Question 14

RNA

Answer 14

Chemical cousin of DNA

• has a ribose instead of deoxyribose
• uracil instead of thymine

Question 15

From DNA to messenger RNA

Answer 15

gene includes introns and exons, the mRNA transcript includes both introns and exons and the introns are spliced out to produce a mature transcript

Question 16

Alternative splicing in the human genome

Answer 16

over 50% of human genes are alternatively spliced which doubles the diversity of mRNAs and proteins

Question 17

Proteome

Answer 17

library of proteins that can be expressed, 67% of the proteome is in the brain

Question 18

AVP1a gene

Answer 18

Men with two copies of the 334 allele of this gene are generally rated lower on the partner bonding scale, have higher incidence of marital crisis and more often enter cohabitation relationships.

Question 19

SNPs in AChE gene

Answer 19

AChE is acetylcholinesterase which regulates ACh levels

- variants are associated with variability in response to AD drugs which inhibit AChE

Question 20

CYP2D6

Answer 20

involved in metabolizing lots of drugs, has multiple variants
- poor, extensive, and ultra-rapid metabolizers

Question 21

pleiotropy

Answer 21

on gene, many functions