Intrapersonal: Genetics

Question 1

Endophenotype

Answer 1

Biological marker of gene expression.

Are clearly defined and closely aligned with genes. Are more reliable than candidate genes and have larger effect sizes.

Question 2

Smoking endophentoype

Answer 2

Nicotine metabolite rate (NMR). Ratio related to nicotine metabolism. Ration of trans 3-hydroxycotinine (3HC) to Cotinine. Higher NMR means faster metabolism.

Question 3

Nicotine and smoking behaviour

Minafo and McNeill (2013)

Answer 3

Biologically driven measured nicotine in the blood. Levels stay steady over the day and spike with each cigarette. Smokers automatically modulate behaviour to maintain strays levels. If given high nicotine cigarettes inhalation falls.

Question 4

Nicotine biological pathways

Answer 4

Cotinine is the main one. CYP2 A/B Are the main metabolites and enzymes. Genes and enzymes involved could lead to candidate genes if controlled.

Question 5

GWAS genome wide association study

Answer 5

Select strongest signal to indicate a section of genome heavily associated with behaviour. Cues location if a gene (chromosome 15) turned out to be in the nicotine receptor

Question 6

Genetic variation in nicotine receptor

Answer 6

Nicotine acetylcholine receptor gene. Version one is G allele creates normal response to nicotine. Version two is A allele creates poor response to nicotine. Increases the risk of heavy smoking.

Question 7

Rodent model chromosome 15

Answer 7

Genetically engineered to remove C15. Measure self admin of nicotine. Showed lower response and less aversive effects usually get with high levels of nicotine so increase doses. Different alleles and genes create small differences that combine to create large effect.

Question 8

Phenotype precision

Answer 8

Lots of noise when measuring alleles and genes. Cigs per day aren’t reliable as they don’t measure inhalation or strength. Purely a behavioural measure, bio is better as explains more variance.

Question 9

Gene Environment interaction

Answer 9

Risk factors additively increase risk, they can be specific to drug phases and not relevant unless that stage is reached. Gene impact can increase or decrease due to enviro. High gene risk can be increased if exposed to trauma, low risk isn’t.