Genotype & Phenotype (OCR A-Level Psychology): Revision Notes
5.3.3 Genotype & Phenotype
Example:
Someone may have the genetic makeup that makes them have the potential to grow very tall (their genotype).
But if they do not get adequate nutrition and take up smoking at a young age etc, their growth will be stunted (their phenotype).
Traits are investigated through:
Family studies:
Looking to see if there is a family history of the trait. E.g. intelligence, alcoholism, depression.
E: May not be strong evidence for genetics as the trait may be because of vicarious reinforcement, not genes.
E: Not always necessarily because you share genetic material but maybe because you share the same environment.
Twin studies:
Looking for the concordance rate between twins. Looking to see if there is a higher concordance in MZ twins.
Identical twins (MZ, monozygotic) - share the exact same genetic make-up.
Non-identical (DZ, dizygotic) - share 50% of genetic material.
Adoption studies:
- Comparing a child's behaviour and characteristics to their biological adoptive parents. Similarities with biological parents = genetic.
Similarities with adoptive parents = social.
P: Selective placement is a problem as children tend to be placed in families with a similar background to their biological parents.
Concordance rates - The probability that a pair of individuals will both have a certain characteristic, given that one has the characteristic (most often used when looking at twins). E.g. if one twin has depression it is likely that the other one will.