Study finds how genetics interacts with social forces, environments
Indiana, US: Humans are a diverse species. Each person on the earth has enough DNA to reach Pluto three times over.
Studying how all of this genetic material works, and especially how genes impact human behaviour, is a very difficult effort aided by the introduction of large banks of genetic data and powerful data science analytical tools to analyse that data.
Robbee Wedow, an assistant professor of sociology and data science in Purdue's College of Liberal Arts, an adjunct assistant professor of medical and molecular genetics in Indiana University's School of Medicine, and Purdue's inaugural faculty-in-residence at AnalytiXIN/16 Tech in Indianapolis, maps those miles of genes to gain insights into how genetics interacts with social forces and environments. He used genetic databases to investigate how single nucleotide polymorphisms, or SNPs, impact complex, encompassing qualities such as sexual behaviour, educational achievement, socioeconomic position, health behaviours, and others.
"We know that social forces like socioeconomic status play a role in influencing a person's life and life outcomes," Wedow said. "But we also know there is a genetic component to every behavior. What we don't understand yet is how these biological forces interact with the environment and what these sorts of interactions might mean for social science -- and what we think we know about social science research to date. We are using well-powered genetic data to do more accurate and replicable social science and to explore what might be possible at the intersection of genetic and behavioral science."
The real scope of genetics became clear when scientists sequenced the first human genome in 2003. Initially, geneticists believed that discovering a gene for each trait was as simple as looking in the appropriate spot.
However, DNA bases and genes are not only keys of a grand piano on which human lives are performed like masterpieces. Instead, DNA functions more like a pipe organ, with stops, switches, and pedals that may alter the tone of notes, muffle them, or enhance their volume. Environment, diet, pollution, life experiences, and other factors may all influence when and how genes matter for specific outcomes, as well as whether parts of the genome matter at all. There is no one gene responsible for a behavioural consequence. Biology does not determine fate: while it does set out the musical score, musicians are free to improvise and interpret as they perform.
The idea, Wedow stresses, is not that these genes control a person's life or destiny. Each SNP, in fact, has a very small effect on an overall outcome like educational attainment. No "Gattaca"-level reading of one's destiny from their genes -- in the style of the dystopian 1990s movie -- is on the horizon. Rather, being able to clarify the genetics of certain behaviors can help scientists understand the nuances of human behavior.
"People think that genetics is always about biology, but in the case of sociogenomics it's more about using the advantages of this new, well-powered data to better understand the outcomes themselves, or about allowing researchers to do more accurate social science and behavioral research," Wedow said. "The social sciences have recently struggled with replicating studies. Oftentimes the sample sizes are too small for rigorous estimates and certainty. That's where the potential of using these huge banks of genetic data for the social sciences comes in. They help us get a much clearer, more certain look at what's really going on."
Analyzing the genetics is only the first step. An American geneticist in the early 1800s could have correlated genetics with educational mastery and concluded that anyone with two X chromosomes tended to have less education. That is not because the chromosomes had anything at all to do with education. Rather, the correlation reflected social and gender biases present in the culture at the time. Similar insights lurk in Wedow's research.
"Sociogenomics isn't necessarily about biology, like some might think," Wedow said. "When someone studies cancer genetics, they are studying it because they want to elucidate the biology of cancer; they want to figure out ways to better diagnose it, track it and treat it. But researchers in the field of sociogenomics want to study the genetics in order to do better social science. No one would ever study sociology without considering socioeconomic status and environment. We want to be able to take genetics into account in the same way."
In a study in volume 7, No. 7 of the journal Nature Human Behaviour, Wedow, his co-corresponding author Andrea Ganna from the University of Helsinki, and his other co-authors looked at 109 survey questions in over 300,000 individuals to examine the ways that people's genes correlated with whether they answered certain questions or left them blank in surveys answered in the UK Biobank. That may sound fairly abstruse, but it fills a gap that the field of sociology has struggled with for decades.
"How do you know what you don't know or how someone might have answered a question if they choose not to answer it?" Wedow said. "It turns out that the genetics of people who either answer the survey question, or do not, overlaps with the genetics of other outcomes like education, income or certain health behaviors."
That means that scientists can use this type of data to get a better understanding of how people who choose not to answer questionnaires might also share similar responses to questions about health or social behaviors. Geneticists can also use the results of this study to correct for bias in genetic studies of any behavioral, psychiatric or medical outcomes.
"We can't parcel out the signal from the noise yet or causally tease apart the effects of environment from the effects of biology," Wedow said. "We know the genetics correlate with certain outcomes, but we are not at a point where we can say any specific gene causes any one outcome. The effect of each individual gene is small. It's only in large data sets that we start to get the statistical power to get meaningful, reproducible results. We are using these new exciting, emerging data and tools to revolutionize social science."
