Methods

• How is variation in family investigated?

  Family studies

  Twin studies (MZ/DZ)

  Adoption studies
• What is the idea behind the methods?

  Share differing proportions of our genetics depending on degree of relatedness - Relates to shared behaviour
• What is the expectation?

  Phenotype tells us about genotype and the roles of genes and environment
• What do Twin studies involve?

  MZ twins - share 100% of genes

  DZ twins - share 50% of genes

  Look at how similar/different twins are on psychological variables and estimate contribution of genes vs the environment
• What do adoption studies involve?

  MZ/DZ twins reared apart vs together

  Different developmental environment

  No shared genes between the child and parent

  Relative contribution of genes and environment on phenotype