Summary Twin Research in Psychology

A snapshot of the summary - Twin Research in Psychology

• Lecture 1A: Historical perspective & Mendel

• Which childhood psychopathology is the most heritable?

  ADHD
• Do genes en environment always play a rol in complex traits?

  Yes
• What did Carl linnaeus?

  He created a system that systematically categorize the different species he saw.
• Explain Mendel's First law: The law of segregation.

  A recessive element is expressed only if both elements are recessive. While a dominant element is expressed when one or two are present.
• For which cases the 2nd Mendel's law applies?

  1. For genes on different chromosomes
     
  2. For genes that are far apart on the same chromosome.
• For which cases the 2nd law doesn't apply?

  1. Linkage: genes are close together on the same chromosome which inhibits crossing.
  2. X-linked inheritance
     
     
• Definition centimorgan (map unit)

  The distance between two loci estimated by the number of recombinations per 100 gametes.
• Examples qualitative traits

  Examples are: HD, PKU and Cystic fibrosis.
• Definition quantitative traits (polygenic/complex traits)

  Traits are influenced by multiple genes. These genes follow a complex pattern of inheritance. The phenotype is expressed on a continuum and the trait expression may be altered by the environment. These traits are nominal distributed in a bell-shaped curve.
• Examples of quantitative traits

  Alzheimer and behavioral traits