If all people were genetic clones, every trait's heritability index would be:

1. Heritability measures how much variation between individuals is due to genetic variation. 2. Clones have no genetic differences, so all variation between them must be environmental. 3. The heritability index of every trait would then be zero. _Source: Wikipedia, "Nature versus nurture" (rev 1379405136), section "Gene–environment interaction"_