PSYC1001 Lecture Notes - Lecture 5: Zygosity, Myelin, Breastfeeding
Genetic Foundations
Genes
• Chromosome - threadlike structure found in the nucleus
• DNA - double-stranded molecule that makes up the chromosomes
• Genes - contains instructions for making particular proteins
o Basic units of heredity
o Each chromosome contains thousands of genes
o Gene is expressed if it has been turned on to make its specific protein
▪ Environment causes expression - conditions of which genes are expressed are different
• Zygote - single cell - combination of 1 sperm (23 chromosomes) + 1 egg (23 chromosomes)
• Genotype - genetic blueprint - DNA passed from parents to child
• Phenotype - observable physical or psychological attributes or qualities
Genes and environment
• Behaviour genetics
o Understanding how genetic and environmental factors combine to produce individual
differences in behaviour
• Heritability
o Degree to which variation in a particular trait is due to genetic differences
o 0 (no heritability) to 1 (completely heritable)
• Kinship studies
▪ Family studies
▪ Twin studies
▪ Adoption studies
o Degree of relatedness
▪ Probability of sharing genes among relatives
▪ Work out the relative contribution of genes and environment to a particular phenotype
▪
• Monozygotic twins
• Share 100% of genetic material
• Dizygotic twins
• 50%
• Siblings but raised in the same conditions
o Heritability estimates for many traits:
▪ Physical characteristics - height 80%
▪ Mental illnesses - schizophrenia 50%
▪ Developmental disabilities - autism 64-91% (range - differs on criteria of diagnosis)
▪ Intelligence
find more resources at oneclass.com
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Document Summary
Zygote - single cell - combination of 1 sperm (23 chromosomes) + 1 egg (23 chromosomes: genotype - genetic blueprint - dna passed from parents to child, phenotype - observable physical or psychological attributes or qualities. Family studies: twin studies, adoption studies, degree of relatedness, probability of sharing genes among relatives, work out the relative contribution of genes and environment to a particular phenotype, monozygotic twins. Share 100% of genetic material: dizygotic twins, 50% Siblings but raised in the same conditions: heritability estimates for many traits, physical characteristics - height 80, mental illnesses - schizophrenia 50, developmental disabilities - autism 64-91% (range - differs on criteria of diagnosis) Low activity: associated with aggression in animals, environment - childhood maltreatment, does maoa activity moderate the effect of maltreatment on the development of antisocial behaviour, maltreatment is a risk factor for antisocial behaviour. Fatty acids in breast milk - important for brain development: omega 3 fatty acid.
