Tuesday, September 6, 2011
"Twin studies are useless"
Interesting article on Slate.com questions the validity of twin studies:
Traditionally measures of heredity for human traits came largely from twin studies: comparisons between identical twins (same environment, same genes) and fraternal twins (same environment, but no more related than any sibling pair).
But it's becoming increasingly clear that the assumptions of these studies are often invalid. Identical twins do not have identical genomes (they can differ in terms of the copy number of genes, for example), and the aspects of genome function are not static - they can change over a lifetime based on environmental factors. Moreover, environmental similarities are probably greater for identical twins: : "As anyone who's ever seen a pair of toddler twins in matching sailor suits is surely aware, monozygotic twins do get special treatment."