Q43 - Twin Studies and Heritability
Most human quantitative traits are affected both by genetics and environment. One way to quantify the relative contribution of genetics versus environment to a given trait is to compare trait covariance (a measure of joint variability of the trait) in pairs of monozygotic (MZ) versus dizygotic (DZ) twins.
True or false?
Q43.1. Such studies assume that all trait covariance between DZ twins is due to shared environment.
Q43.2. Such studies assume that all trait covariance between MZ twins is due to shared genetics.
Q43.3. Such studies assume that environmental exposure covariance is the same between MZ and DZ twins.
Q43.4. For a trait with a very strong genetic contribution, the trait covariance in MZ twins is expected to be higher than in DZ twins.
Q43.5. Non-twin siblings are equally as suitable as DZ twins for such studies as genetically they are equally similar.
Question reproduced from IBO 2023, Theoretical Paper 2, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF