Lecture 11: Behavioural Genetics

• What is the focus of the study of Behavioural Genetics?

  Brain, behaviour and cognition
• What is the relationship between genes and environment in Behavioural Genetics?

  • Combination of both genes and environment
  • Contribution of genes can be surprising
  • Example: Facial expressions in blind individuals
• What did Peleg (2006) find about facial expressions?

  Blind people have similar expressions to sighted relatives
• What does the study of identical twins reared apart illustrate?

  • Similarity in behaviours and traits
  • Example: Holding beer cans similarly
• What is the current focus in the nature vs. nurture debate?

  Relative contributions of nature and nurture
• What is required to understand the interaction of genes and environment?

  Understanding of molecular genetics
• Who discovered the structure of DNA?

  Watson and Crick
• What are the four types of nucleotides in DNA?

  Adenine, guanine, thymine, cytosine
• How are the two strands of DNA structured?

  Coiled into a double-helix running opposite directions
• What holds the nucleotides together in DNA?

  Hydrogen bonds between specific partners
• What is the significance of the order of nucleotides in DNA?

  It codes for genetic information
• How long would the DNA in a single human cell be if stretched out?

  About 2 metres
• How many chromosomes do humans have?

  46 chromosomes (23 pairs)
• What determines the sex of a child during reproduction?

  The X or Y chromosome contributed by the male
• What happens when a cell divides regarding DNA?

  The DNA helix is "unzipped" for replication
• What can happen during DNA replication?

  Errors may occur, leading to mutations
• What is the process of creating RNA from DNA called?

  Transcription
• What is the main difference between RNA and DNA?

  RNA has uracil instead of thymine
• What does messenger RNA (mRNA) do?

  Carries protein-building messages encoded by nucleotides
• What is the result of the translation process?

  A sequence of amino acids forming a protein
• What is a codon?

  A genetic word of three bases
• How many codons are there in total?

  64 codons
• What is a base-pair substitution mutation?

  Replacement of one nucleotide and its partner
• What is the Human Genome Project?

  It sequenced the full human genome
• What does being homozygous for a gene mean?

  Identical pair of genes on chromosomes
• What does being heterozygous for a gene mean?

  Unmatched pair of genes on chromosomes
• What are the types of genes based on their effects?

  Dominant, recessive, or intermediate
• How does a dominant gene behave in homozygous and heterozygous conditions?

  Shows a strong effect in both conditions
• What is a recessive gene's effect?

  Shows effect only in the homozygous condition
• How does genetic sensitivity to bitter taste affect behaviour?

  • Dominant gene enhances bitter taste sensitivity
  • Helps avoid toxins in early humans
  • Modern implications: Less likely to smoke or eat certain vegetables
• What factors can influence the ability to taste PTC?

  Diet, mouth dryness, and sensitivity changes
• What is epigenetics and its significance?

  • Genes active at specific life stages or times
  • Changes in gene expression affect learning and memory
  • Explains differences between identical twins
• What does heritability refer to?

  Dependence of characteristics on genetic differences
• How do researchers study heritability?

  By studying twins and adopted children
• What can traits with strong hereditary influence be modified by?

  Environmental intervention
• What is the twin study method in Behavioural Genetics?

  • Compares similarity between MZ and DZ twins
  • MZ twins share 100% DNA
  • DZ twins share approximately 50% DNA
• What does the ACE model in twin studies represent?

  A = Additive genetic effect, C = Shared environment, E = Non-shared environment
• What does an h2 value of 0 indicate?

  No heritability or genetic influence
• What does an h2 value of 1 indicate?

  Trait is entirely due to genetics
• What are non-shared environmental influences?

  Unique influences making individuals different