Psychology 3442F/G Lecture Notes - Lecture 5: Epigenetics, Phenotype, Heritability
26 Oct 2017
School
Department
Course
Professor
Lecture 5: Genetics & Education
Quantitative Genetic Model: dominant model in estimating heritability
-twin studies —> MZ twins share 100% of genes & DZ twins share 50%
Phenotype: observed characteristic of individuals resulting from combined effect of genes &
environment (height, grades, personality)
-shared environment accounts for what you experience differently ** in MZ
Phenotype Variance: variation in the trait within the population
-twin studies aim to estimate phenotypic variance explained by genes & the environment
ACE Model: Additive Genetic (A), Shared environment (C), Non-shared environment (E)
1. Heritability = proportion of phenotypic variance ascribed to heritable genetic influences
-twice the difference bt MZ & DZ
-Because:
-rmz = A + C
-rdz = 1/2A + C
-A = 2(rmz - rdz) (2x difference bt MZ & DZ)
2. Shared Environment = familial resemblance not explained by heritability
-C = rmz - A
-left over similarities from genes in shared environment
3. Non-Shared Environment = any similarities accounted for by A & C is due to E
-E = 1 - MZ
-the remaining unexplained variance in MZ twins
Heritability: doesn't mean genes have causal effects
-doesn't mean that if something is heritable it cannot be changed
-is about variation in population not in individuals
Teds Study: identified twins bt 1994-1996
-over 15000 pairs have been enrolled
-assessed at 2, 3, 4, 7, 9, 10, 12, 14, 16, 18 yo
High heritability doesn't mean education system is good … system is equitable
-the national curriculum is ensuring all children are getting the education they are intended on
getting
Discussion: Do these findings mean that schools do not count?
Whats the role of the educational system? How does it influence heritability estimates?
Political Reaction in UK; genetics are more important than teaching
-Michael Gove — IQ, not education which determines a childs future
Literacy more relevant in primary years
9 Predictors of Educational Achievement:
-intelligence, self efficacy, school environment, home environment,
personality, well-being, parent-reported behaviour problems, child
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Quantitative genetic model: dominant model in estimating heritability. Twin studies > mz twins share 100% of genes & dz twins share 50% Phenotype: observed characteristic of individuals resulting from combined effect of genes & environment (height, grades, personality) Shared environment accounts for what you experience differently ** in mz. Phenotype variance: variation in the trait within the population. Twin studies aim to estimate phenotypic variance explained by genes & the environment. Ace model: additive genetic (a), shared environment (c), non-shared environment (e: heritability = proportion of phenotypic variance ascribed to heritable genetic in uences. Twice the difference bt mz & dz. A = 2(rmz - rdz) (2x difference bt mz & dz: shared environment = familial resemblance not explained by heritability. Left over similarities from genes in shared environment: non-shared environment = any similarities accounted for by a & c is due to e. The remaining unexplained variance in mz twins.
