Week 9 genetics of intelligence

What is the IQ correlation for parent-child? (Bouchard and McGue)

0.42

What is the IQ correlation for siblings? (Bouchard and McGue)

0.47

What is the correlation for IQ between DZ and MZ twins?

DZ - 0.60

MZ - 0.86

What did Turkheimer 2003 find in their twin study?

proportions if IQ variance attributable to genes and enviro vary non linearly with SES

lower SES families - 60% variance in IQ scores was accounted for by shared enviro and contribution of genes was close to zero

The Bell Curve arguement?

African Americans have lower IQ scores

IQ highly heritable

What do heritability estimates not tell us?

how much of your IQ is due to your genetics

What is the Wilson effect?

the increase in heritability of IQ with age

What is the multiplier effect?

genetic tendencies that guide behaviour will result in a change in the enviro that magnifies the original tendency

What is an SNP?

variations in a single DNA building block (nucleotide) that occur frequently in the population

What did Davies et al 2018 find about genetic effects on intelligence?

are 11600 significant SNPs (one SNP was related to having another SNP)

only 434 of these were independent SNPs though

709 genes were associated with intelligence

Evidence for intelligence being a polygenic trait?

Davies et al 2018 found 709 genes involved with intelligence

25% of the variation observed in participants intelligence test scores was accounted for by DNA SNP variation

What do the genes and DNA variations involved in intelligence do?

many of these genes were related to the dev of nerve cells and NS

some of the SNP variations also related to health (height, weight, BMI, SZ, Alzheimers)

How do we test the correlation between g ad nerve conduction velocity?

measured by applying a burst of current through skin over nerve and picking up its time of arrival further up or down nerve

good correlations with IQ