Mr Bouchard's studies suggest that the level of one's intelligence is, in the jargon, "69-78% heritable"—heritability being the proportion of the difference between people that is acquired through the genes, not life itself.
However, for variations to have evolutionary effect they need to be (at least partly) hereditary or heritable (see entry on heritability; I will here focus on hereditary variations and hereditary transmissibility as defined above, and will not discuss the notion of heritability which is a population term).
The more demanding population genetic definition of heritability is that a heritable trait T is one where variation in T can be accounted for primarily by variation in genes as opposed to variation in the environment (see also the entry on heritability).
Effects like these show up in heritability analyses as statistical interactions between genes and environment, meaning that how heritable the trait is depends on the specific distribution of environments across the population.
Height, for instance, is now around 90% heritable in rich countries.
Epigenetic changes are heritable changes to the regulation of a cell's genes, caused by extra molecules being attached to those genes.
(Studies of identical and non-identical twins suggest that co-operative behaviour in trust games is heritable).
Such competence is potentially heritable and is reinforced by the human tendency to mate with partners of similar traits and ability.Bob's your uncle, unfortunatelyThis is a distressingly fatalistic view of opportunity.
He was trying to make the slippery problem of the evolution of human culture as tractable as that of biological evolution, and he thought that if cultural information could somehow be divided into separately transmissible elements, in the way that biologically heritable information is divided into genes, the rest might follow.
Several thousand human genes are linked, when they fail to work properly, to more than 4,000 heritable genetic diseases.
Some studies have suggested that homosexuality is around 50% heritable.
