Expanding on a study from earlier in 2017 that identified 52 genes that could be associated with intelligence, an international team of researchers has now suggested dozens of new genetic targets that may correlate with cognitive ability. The new study also found that many of these genes, potentially responsible for intelligence, could overlap with a range of conditions from increased lifespan to some autoimmune disorders.
The heritability of intelligence is quite reasonably a source of controversy amongst many scientists, and it is fair to say there is debate over how to quantify a trait as complex and indefinable as intelligence. This particular study focused on using a measure of the highest level of education as person has achieved as a marker of cognitive ability.
The researchers do note that this is a measure that can be influenced by a variety of unrelated factors. For example, socio-economic status or personality traits can notably influence the level of education a person reaches regardless of any "genetic intelligence" traits. The study does suggest that other reports have confirmed educational attainment and cognitive performance have been consistently correlated, and the sheer scale of the sample size this measure allows make it a reasonably useful factor to work off.
The most interesting result of this kind of study is in its examination of the genetic correlations between these suspected intelligence genes and other disparate conditions. In this case a fascinating fundamental genetic correlation was identified between cognition and aging, with an association seen linking higher cognitive ability with a longer lifespan. Another odd genetic correlation identified was a relationship between higher cognition and increased instance of celiac disease.
The ultimate goal of this research is to help direct research into gene therapies that can help treat neurodegenerative disease. By understanding what genes directly enhance cognitive ability scientists hope to be able to better fight those diseases that erode our cognitive mechanisms.
"For the first time, we were able to use genetic information to point us towards specific drugs that might aid in cognitive disorders of the brain, including Alzheimer's disease, schizophrenia and attention deficit hyperactivity disorder," explains senior author of the study Dr Todd Lencz.
It is worth taking these genetic intelligence studies with a grain of salt. If anything, the more genetic overlap that is identified by these studies the more we realize how complex our genetic functions truly are. The reality is it's not as simple as triggering a single gene to make one smarter, but Dr Lencz does note that as we collect more data these studies will become more and more accurate.
"Because the number of genes we can discover is a direct function of the sample size available, further research with additional samples is likely to provide even more insight into how our genes play a role in cognitive ability."
The study was published in the journal Cell Reports.