9. Evaluating Data On Phenotypes

Question 1

What is a phenotype ?

Answer 1

Organismas genotuoe and the interactsction of genotype with environment

Question 2

Example

Over eating

Answer 2

Was thought to be environmental - more food in developed countries

Food consumption increases brain dopamine levels in animals one enough dopamine was released people would stop eating

People with one particulate allele has 30% fewer dopamine receptors - more likely to overeat - wouldn’t stop eating when dopamine levels increases

Question 3

Antioxidants

Exmpale

Answer 3

Many foods contain amgioxidants - prevent chronic diseases
Berries contain high levels of antioxidants - plants which produced them contained different levels of antioxidants bextSe of genetic factors.

Environmental conditions called great variation so both genetic and environmental

Question 4

Identical twins

Answer 4

Differences in phenotype must be entirely down to environmental factors

Very similar epigenetic markers when born.

If characteristic is very similar in both twins that was probably genetic but characteristic is different environment would have played bigger role - diet / excerise

Question 5

Alzheimer’s diseases in identical twins and non identical twins

Answer 5

Diseases has genetic risk

But disease not always found in both twins which suggest that environmental factors also play a part

Genetics account for 80% of risk

Question 6

Why need lots of twins?

Answer 6

Valid conclusions

Small sample less representative of population