Gene Environment Interaction

Question 1

What was Galton’s assumption about nature/nurture?

Answer 1

Believed everything was controlled by genetics; a gene for crime, gene for intelligence

Question 2

What well-known genetic mutation is commonly seen in obese lab mice?

Answer 2

Leptin protein

Question 3

What does the Leptin protein do?

Answer 3

Informs fullness, when to stop eating

Question 4

What is some behavioural evidence for the role of genetics in obesity?

Answer 4

Identical twin studies, when asked to eat as much as they feel will will tend to put on and lose weight together

Question 5

How does FTO gene affect obesity?

Answer 5

Changes appetite by making food more attractive, compulsive eating similar to drug addiction

Question 6

What FTO mutation is responsible for behavioural changes?

Answer 6

Changes in two base pair, AA (normal) changed to TT (increased appetite)

Question 7

What is some statistical evidence for environmental effects on obesity?

Answer 7

Food much cheaper, less healthy, and obesity more of an issue among lower classes (who cannot afford healthy food)

Question 8

What is some experimental evidence for environmental effects on obesity?

Answer 8

Starved mice are still thin no matter their genetics

Question 9

How is gene expression in alligators famously controlled by environment?

Answer 9

Temperature-dependent sex determination

Question 10

What is an example of temperature-dependent gene expression in drosophila?

Answer 10

Eye color mutation, white eyes develop in high temperatures and dark brown eyes at low temperatures

Question 11

How are temperature-sensitive mutations used to study development?

Answer 11

1/5 new mutations are viable at 20 degrees, lethal at 30; changing temperature for short periods of development can show when certain genes are activated

Question 12

How do arctic hares make their fur white in preparation for winter?

Answer 12

Less light during shorter days leads to black pigment genes being switched off

Question 13

How to trees know when to drop their leaves?

Answer 13

Light-sensitive expression of death-gene in leaves, switched on when days go shorter

Question 14

How is light-sensitive gene expression possibly useful for humans?

Answer 14

Possible influence on seasonal affective depression

Question 15

What mutation prevents E. coli from growing in tryptophan-free environments?

Answer 15

Tryp-minus, prevents them from being able to synthesise their own tryptophan

Question 16

What is phenylketonuria?

Answer 16

Mutation in humans that causes loss of ability to metabolise phenylalanine

Question 17

What are the effects of phenylketonuria?

Answer 17

PhA present in nearly all food, so inability to metabolise causes unhealthy eventually fatal buildup of PhA

Question 18

How can phenylketonuria be detected?

Answer 18

Guthrie test, uses a PhA-minus bacteria to test blood for buildup of PhA

Question 19

How can phenylketonuria be controlled environmentally?

Answer 19

PhA-free diet

Question 20

What is the pathology of porphyria?

Answer 20

Inability to break down red pigment in blood, cannot do out in the day, can go mad

Question 21

What environmental change triggered porphyria-like disease in south africa?

Answer 21

Introduction of barbituate drugs

Question 22

Why can 10% of the population feel no analgesia from codeine?

Answer 22

Lack gene that metabolises codeine into morphine

Question 23

What mutation was responsible for the discovery that certain women experiences a 35x increased risk of thromboembolism following use of a contraceptive pill?

Answer 23

Factor V Leiden, carries base 6-fold increased risk, jumps to 35-fold when paired with certain contraceptive pill

Question 24

How is Huntington’s Disease affected by environment?

Answer 24

Only expresses at a certain age

Question 25

What is one common way that dominant traits can skip generations and be seen as recessive on pedigrees?

Answer 25

Incomplete penetrance

Question 26

What factors can influence the penetrance of a mutation?

Answer 26

Developmental environment, post-natal environment, expression of related genes, etc.

Question 27

What is the difference between penetrance and expressivity?

Answer 27

Penetrance is a change all-or-none expression of a gene, expressivity is a change in degree of expression along a spectrum

Question 28

What gene has been touted as a Galtonesque ‘gene for crime’?

Answer 28

Monoamine oxidase gene in amygdala, different activity changes fear response to a fearful face (little evidence for this influencing criminal behavior)

Question 29

What gene is present in 50% of the population that increases criminal activity 10-fold?

Answer 29

TDF, male determining factor on the Y chromosome

Question 30

What is statistical evidence for environmental influence on criminal behaviour?

Answer 30

Crime rates follow gang activity, firearm availability, social stress; 25 murders/million people/year in UK vs 1000 in colombia (sorry nico)