Twin studies

Question 1

What can twin studies provide evidence for?

Answer 1

Genetic / Environmental variation

Question 2

How are Monozygotic twin studies carried out?

Answer 2

1. MZ twins have the same genotype - geneticaly identical
2. They are separated at birth and grow up into different environments
3. Both are then given an IQ tests
4. If the concordace in IQ scores is
   - Over 85% - IQ is mainly genetically controlled and is largely unaffected by the environment
   - Under 20% - IQ is not genetically controlled and is largely affected by the environment

Question 3

How are dizygotic twin studies carried out?

Answer 3

1. Have a 50% similar genotype
2. They are grown in the same environment
3. Both are then given an IQ test
4. If the concordance in IQ scores is
   - Over 85% - IQ is mainly environmentally controlled
   - Under 20% - IQ is mainly genetically controlled

Question 4

What are some problems with twin studies?

Answer 4

1. Biologist chooses the twin pairs
2. Sample size of identical twin pairs is very small - not enough twin pairs to study