Heritability

Genome-wide association studies establish that human intelligence is highly heritable and polygenic

http://www.nature.com/mp/journal/v16/n10/full/mp201185a.html

We found that individuals with high IQ show high environmental influence on IQ into adolescence (resembling younger children), whereas individuals with low IQ show high heritability of IQ in adolescence (resembling adults), a pattern consistent with an extended sensitive period for intellectual development in more-intelligent individuals.

http://pss.sagepub.com/content/early/2013/07/01/0956797612473119.abstract

Common DNA Markers Can Account for More Than Half of the Genetic Influence on Cognitive Abilities
For nearly a century, twin and adoption studies have yielded substantial estimates of heritability for cognitive abilities.We found that DNA markers tagged by the array accounted for .66 of the estimated heritability, reaffirming that cognitive abilities are heritable.

Robert Plomin -  Institute of Psychiatry, King’s College London
http://pss.sagepub.com/content/early/2013/02/22/0956797612457952.abstract