I also don't think you can separate genetic influences from environmental influences, i.e. one allele might make you do well in one environment and poorly in a different environment. This appears to the case for the 7R allele of the DRD4 gene: http://www.northwestern.edu/newscenter/stories/2008/06/ariaa...
I also don't think any genes actually code for intelligence as it's commonly understood. Intelligence is, basically, knowledge (including knowledge about how to acquire knowledge). Genes affect brain chemistry, which influences intelligence in different ways, within a given environment.
> Intelligence tests and psychometrics have generally found high correlations between different aspects of intelligence, rather than the low correlations which Gardner's theory predicts, supporting the prevailing theory of general intelligence rather than multiple intelligences (MI).[19] The theory has been widely criticized by mainstream psychology for its lack of empirical evidence, and its dependence on subjective judgement.[20]
I have no idea how football fairs, but you can debate the usefulness of that as an objection to the validity of IQ with someone else.