PSY236 Lecture Notes - Lecture 7: Natural Selection, Lysine, Mitosis
2 Jun 2018
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PSY236: Behavioural Neuroscience – Genetics
Behaviour: nature vs. nurture
• Behaviour is the response of an individual, group or species to stimuli (trigger)
in the environment
• Why do people respond differently to a similar environmental trigger?
o Their genetic makeup (nature)
▪ Evolution e.g. human vs. bird
▪ Parental traits (colour of skin, height, intelligence, ability to
sing)
o Factors in their environment (nurture/experience)
▪ How they are ‘feeling’ at the time (hungry, tired, happy)
▪ Previous experiences (or taught a skill or how to behave)
▪ Culture
Chromosomes
• Chromosomes are found in every cell of our body
• They contain our genetic material = genes
• Genes drive the function of our cells (manufacture proteins)
• Chromosome = one strand
o Can look like two strands; this is the stage in the cell cycle where the
cell has been duplicated
o Usually you see them as a duplicated chromosome
• Human has 46 chromosomes
o 23 pairs (of pairs)
o It is unusual to see chromosomes as single structures as they are
usually in a replicated stage
o So there are two of each (sister chromatids) joined together at the
centromere
• Females have XX, males have XY
▪ Females will always contribute an X chromosome to offspring
and males will give X or Y (males determine the sex of child)
What are genes?
• Genes are regions of DNA that are units of hereditary (information can be
passed from one generation to another)
• DNA = double strands of nucleotide ‘base-pairs’ on chromosomes
• These are in the NUCLEUS of cells (animals and plants)
• What is a nucleus?
o A membrane bound part of a cell which contains all genetic
information to promote survival of the cell (organism)
o Cells are present in all body parts – group of cells make an organism
o Each cell contains a nucleus and contains chromosomes made up of
genes
• Chromosomes are made up of genes
• Particular sequences of DNA are known as genes
• DNA is essential for life: the DNA in each gene programs the manufacture of
different proteins for use in the body
• Proteins are made up of amino acids
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