Er, no. Quite unlike hair colour. Much more like a more complex version of height. MUCH more complex. There is undoubtedly a genetic component. But height is also determined by nutrition, and nutrition at certain stages of development.
Families MAY share general 'intelligence' levels. But they also share religion and language. And these are in no way determined genetically.
And then we have the complexity of 'intelligence'. The genetic component will be determined by many, many genes (one assumes). These are highly unlikely to be simply cumulative. It is much more likely that they will their effects will determined by the rest of the gene complementation. For example, allele X of gene A will make you smarter when it is present with allele M of gene B. But if you have allele O of gene B then allele X of gene A will be disadvantageous. We see these effects in the relatively simple genetic resistance to disease - indeed in nearly all 'many gene' complex characteristics.
So while the above is probably the best description of the likely relationship between genes and intelligence - it is not a simple clever + clever = clever equation.
Families MAY share general 'intelligence' levels. But they also share religion and language. And these are in no way determined genetically.
And then we have the complexity of 'intelligence'. The genetic component will be determined by many, many genes (one assumes). These are highly unlikely to be simply cumulative. It is much more likely that they will their effects will determined by the rest of the gene complementation. For example, allele X of gene A will make you smarter when it is present with allele M of gene B. But if you have allele O of gene B then allele X of gene A will be disadvantageous. We see these effects in the relatively simple genetic resistance to disease - indeed in nearly all 'many gene' complex characteristics.
So while the above is probably the best description of the likely relationship between genes and intelligence - it is not a simple clever + clever = clever equation.
