PSYO 2160 Lecture Notes - Lecture 3: Phenylalanine Hydroxylase, Punnett Square, Phenylalanine
3 May 2018
School
Department
Course
Professor
Guest Lecture: Molecular Genetics and Development
September 18, 2015
Behavioural Genetics: broad field of research that examines how genetics influence behaviour
• Nature vs nuture
• Complex interplay of genes and the environment
Interdisciplinary field: psychology, biology, neuroscience, ethology, genetics
Genes – functional unit of heredity
*see transcription and translation & DNA vs. RNA
Principle of segregation: each gamete carries only one allele because the alleles have segregates
during meiosis
Mendel’s Law of Independent Assortment: the presence of an allele of one of the gene in a gamete has
no influence over which allele of another gene is present (only holds true for unlinked genes on
different chromosomes)
Punnett Square:
• Ex. Bb x bb: ½ Bb, ½ bb
• Dominant and recessive genes
Genes can be manipulated through selective breeding as exhibited in Mendel’s experiment with pea
plants. Another example is selective dog breeding.
• Few genes are dedicated to behavioural function
• Genes influence the expression of a behaviour pattern
• Genes influence neural function
• Genes influence development
Ex. Drosophila foraging gene
• Rover vs. sitter larvae
• Differ in foraging behaviour
• Difference is due to a single gene
• Gene encodes an essential gene PKG which is important for intracellular signaling
• Rovers have higher PKG activity
• Both rovers and sitters forage when food is limited
• Difference only observed when food is abundant
Ex. Ruff Bird
• S allele – dominant, satellite male; s allele – recessive, independent male behavioral
dimorphism
Pleiotropy
1. Gene has multiple effects on the phenotype of an organism
2. Gene influences two or more seemingly independent phenotypic traits
Ex. Phenylketonuria absent phenylalanine hydroxylase enzyme activity
• Cannot break down excess phenylalanine
• Leads to intellectual disabilities
• Can be controlled by environmental factors (diet)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Behavioural genetics: broad field of research that examines how genetics influence behaviour: nature vs nuture, complex interplay of genes and the environment. *see transcription and translation & dna vs. rna. Principle of segregation: each gamete carries only one allele because the alleles have segregates during meiosis. Mendel"s law of independent assortment: the presence of an allele of one of the gene in a gamete has no influence over which allele of another gene is present (only holds true for unlinked genes on different chromosomes) Bb x bb: bb, bb: dominant and recessive genes. Genes can be manipulated through selective breeding as exhibited in mendel"s experiment with pea plants. Another example is selective dog breeding: few genes are dedicated to behavioural function, genes influence the expression of a behaviour pattern, genes influence neural function, genes influence development. S allele dominant, satellite male; s allele recessive, independent male behavioral dimorphism.
