In this new study in Intelligence, Add Health Study data is used to compare the average level of dopamine-related alleles among students of 36 different middle and high schools. This measure is strongly associated with lower mean IQs (Beta = -.47). The relationship is weakened substantially (to Beta = -.35) when the percent of the school that is black is added as a control in the OLS regression model.
What's the interpretation of this in plain English? It is this: Some schools have a higher percent of students with genes associated with a low IQ. These schools tend to have a low average IQ. So one important cause of low-IQ schools is having more kids with the bad genes. What the percent black predictor tells us is that: 1) schools with more blacks tend to have more students with the at-risk genes; 2) schools with a higher percent of blacks have lower intelligence levels; and 3) evidently an important reason why some schools are smarter than others is due to having fewer blacks--a group which has a higher prevalence of the bad genes.
This study contradicts the view that: 1) race is a social construction, and 2) the black-white gap in IQ has nothing to do with differences in genes.