The human genome

  • 000 – 30.000 genes
  • Stored as DNA sequences within 23 chromosome pairs
  • 2% of genes cause protein coding (98% do …?)
  • 99% of genes similar between humans, 1% make us unique.

tehavioral genetics

  • Interested in the influence of genes on psychological function.
  • Genotype: Genetic structure
  • Phenotype: Observable psychological function

Relatedness

  • The probability of sharing a gene with someone.

Heritability (h^2) (Often misunderstood)

  • Statistical definition: h^2 is the proportion of phenotypic variance attributable to genetic variance.
  • Common sense definition: h^2 is the extent to which individual differences in observed behavior can be explained by genetic individual differences.
  • Heritability = The proportion of phenotypic variance in a group of individuals that can be explained or accounted for by genetic variance.
  • H = 20  20% = GV, 80% = Environmental

Selective breeding

  • The process of selectively breeding plants and animals for specific traits.

Adoption studies

  • A way to disentangle genetic and environmental sources of family resemblance.
  • Issues:
    • Representativeness: Are adopted children and their families representative of the general population?
    • Selective placement: If adopted children are placed with adoptive parents who are similar to their birth parents, then this could blur the conclusions for adoption studies.

Twin studies

  • Monozygotic (Share 100% of genetic material) –   Dizygotic (On average share 50% of genetic material) –      Issues:
  • EBual environmental assumptions: The environments experienced by MZ twins are no more similar than the environments experienced by DZ twins.

(Overestimation of heritability if assumption is violated)

  • Assortative mating: Mating pattern where individuals with similar genotypes and/or phenotypes mate more with one another more frequently than what would be expected under a random mating pattern.

Shared versus non-shared environments

  • Shared: both siblings have a television in their house.
  • Non-shared: Siblings are treated differently by parents and have different friends.

behavioral genetic research has findings in:

  • Political Interests
  • Smoking behavior
  • Artistic, technical and cultural interests

Genotype-environment interaction

  • Differential response of individuals with different genotypes in response to the same environment.
  • Example: effect of noise on extraversion. – Passive/reactive