Psychology
February 27, 2013
• Genetics basics
• Chromosomes contained in the nucleus
• 23 pairs of chromosomes
• A gene is a segment of a DNA strip
• mRNA forms complementary to the DNA strip
• mRNA codes for amino acid sequences
• Amino acid sequences form proteins
• Mendelian genetics
• Allele = portion of a chromosome that is coding for a particular characteristic
• Pairs of alleles (one on each chromosome)
• Heterozygous vs. homozygous
• Complete dominance: the dominant allele dictates the characteristic
• Incomplete dominance: the dominant/recessive alleles “mix” to create an intermediate trait
• Genotype, phenotype, and environment
• Environment can impact genes
• Especially in the womb
• Environment can impact phenotype
• Your genes/phenotype can impact your environment
• Genes + Environment = Phenotype
• E.g.: the rabbit + cold = black fur
• Intelligence: genes + environment
• Animal models
• Genetic component: Benefit - selective breeding (strain of more intelligent vs. strain of less intelligent rats)
• Environmental component
• Upbringing - enriched vs. impoverished
• Breeding maze dull vs. maze bright rats
• Results: rats tend to be more polarized in their maze intelligence with higher generation
• So genes do dictate intelligence...but not exclusively. Environment has a big impact too. • Rats in impoverished environments: big difference between maze bright and maze dull strains
• Enriched environment: small/no difference between bright and dull strains
• But human tests show different results
• Environment turns genes on and off
• Environment impacts phenotype
• Heritability - the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals
• Environment impacts heritability
• How much of the variation can be accounted for by genes?
• Heritability within groups = 100%
• Evaluating genes vs. environment
!
• Twin studies
• Monozygotic twins (MZ) = identical
•
• Genetics basics
• Chromosomes contained in the nucleus
• 23 pairs of chromosomes
• A gene is a segment of a DNA strip
• mRNA forms complementary to the DNA strip
• mRNA codes for amino acid sequences
• Amino acid sequences form proteins
• Mendelian genetics
• Allele = portion of a chromosome that is coding for a particular characteristic
• Pairs of alleles (one on each chromosome)
• Heterozygous vs. homozygous
• Complete dominance: the dominant allele dictates the characteristic
• Incomplete dominance: the dominant/recessive alleles “mix” to create an intermediate trait
• Genotype, phenotype, and environment
• Environment can impact genes
• Especially in the womb
• Environment can impact phenotype
• Your genes/phenotype can impact your environment
• Genes + Environment = Phenotype
• E.g.: the rabbit + cold = black fur
• Intelligence: genes + environment
• Animal models
• Genetic component: Benefit - selective breeding (strain of more intelligent vs. strain of less intelligent rats)
• Environmental component
• Upbringing - enriched vs. impoverished
• Breeding maze dull vs. maze bright rats
• Results: rats tend to be more polarized in their maze intelligence with higher generation
• So genes do dictate intelligence...but not exclusively. Environment has a big impact too. • Rats in impoverished environments: big difference between maze bright and maze dull strains
• Enriched environment: small/no difference between bright and dull strains
• But human tests show different results
• Environment turns genes on and off
• Environment impacts phenotype
• Heritability - the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals
• Environment impacts heritability
• How much of the variation can be accounted for by genes?
• Heritability within groups = 100%
• Evaluating genes vs. environment
!
• Twin studies
• Monozygotic twins (MZ) = identical
•