I find this study very interesting because there are a number of provocative ways to interpret the results of this study, and most of those would be incorrect! In what follows, I highlight four (wrong) ways to interpret the results of this study.
I. HA! At last there is proof that genes do influence education attainment!
The first reaction to this result is likely to be a confirmation of something we all know intuitively--our genes influence our behavior, and in particular, the kinds of behaviors that are associated with longevity in school (e.g., perseverance, cognitive ability, work ethic). Unfortunately, its not a good idea to interpret this study as definitive evidence that genes influence educational attainment. Sure the sample of 120,000 people is pretty impressive, but the reality is that the three significant SNPs account for roughly 2% of the variance in participants' educational attainment--or about one extra month of schooling. Not a huge genetic impact on educational attainment, which then might lead someone to conclude...
II. HA! At last there is proof that genes don't influence education attainment!
It seems reasonable to conclude that if SNPs only account for 2% of variance in educational attainment, then they don't matter in the grand scheme of our educational lives, but that would also be an incorrect characterization of these findings. This specific study is a genome wide association study that looks for associations between SNPs and a specific phenotype. The method assumes that there will be relationships between a specific repeating DNA nucleotide sequence and a behavior. This of course, is not the only way that genes can influence us: For instance, genes can have additive effects, can interact with each other or the environment, can be switched on and off by changes in the social context, can mutate, and on and on. This specific study doesn't account for these more complex genetic influences--genes still are very much in play when it comes to educational attainment.
III. This research validates previous SNP studies!
You might be tempted, at this point, to conclude that the results of this study provide further validation for similar work that examines associations between specific SNPs and behavior. Most people are aware of SNPs like those that predict Alzheimer's Disease risk (APOE-4) or that relate to the number of oxytocin receptors in the brain (rs53576). But this specific study, if anything, is actually critical of much of this prior work.
If exploring the entire genome yields specific SNPs that only explain 2% of variance in a given behavior, then that behavior is either uniquely not influenced by genes (see point II above) or SNPs are not likely to be powerful predictors of behavior to begin with. Thus, studies that examine specific SNPs should be using a much larger sample than they have previously (try 120,000).
IV. Gene researchers shouldn't bother with SNP studies
Before you go throwing out the baby with the bathwater, it is important to note that some SNPs are powerful in predicting behavior--though they are fairly rare. The one example is the APOE-4 SNP that predicts Alzheimer's Disease. There are likely others, so this type of research isn't a lost cause. The question of whether a specific SNP sequence will reliably influence complex behaviors that people study in social and personality psychology remains a mystery.
Rietveld, C. A. (2013). GWAS of 126,599 individuals identifies genetic variants associated with educational attainment Science