DNA can identify with almost absolute certainty the person that entered a house and stole a priceless artwork, but had carelessly left a tissue with a few cells on it. Each one of us has a unique combination of polymorphisms – genes that often differ by only a single nucleotide molecule (SNP). The same situation applies to our ancestry. Our DNA bears unequivocal nucleotidal evidence of where our ancestors are from – Asia, Africa, Europe, America, etc.

When it comes to our individuality and our ancestry, there is a remarkable degree of specificity in our DNA. Your genes define you, the individual, with almost 100% accuracy.

It appears that the opposite is true for intelligence. No set of genes has been able to sort out ‘smart’ individuals from ‘dumb’ ones, however such odious terms may be defined for the purposes of a study. A review of intelligence and quantitative trait loci suggests that a particular set of genes may contribute 0.1% or less to the intelligence phenotype of a person. Simple genetic correlations do not define intelligence.

This should not be too surprising for evolutionary reasons: hominids have probably been around for millions of years, H. sapiens only for about 200,000. Human intelligence is a very deep and common feature of all of us. There are definite superficial variations, e.g. “intelligence runs in the family”. Geniuses of various kinds are also hard to explain but these variations seems to have very little to do with the totality or core of human intelligence – the amount of ‘information processing’ that is necessary in order for us to perform at any level is vast, beyond comprehension.

Attempts, therefore, to correlate intelligence with ethnicity, culture, race, class or other physical feature are doomed to fail. Phrenology is a quaint example of how this futile goal did lead people astray. Unfortunately and sadly, many communities, cultures or ethnic groups make a huge deal out of such illusions and waste their time in the pursuit of these very harmful fallacies. 😦