GeneBites

We usually think of DNA as a blueprint for physical traits like eye color and height. But our genes also quietly shape how we experience the world, respond to stress, and form and sustain relationships. This is nature vs. nurture in action.

Image from Pexels.

The nature vs. nurture debate explores how our everyday behaviors are influenced by either our genetics or our environments. The general consensus recognizes that rather than one being more dominant, it is a dynamic balance between the two. What has historically been viewed as a race between nature and nurture is, in reality, more of a relay, one handing off the baton when the skills and traits of the other are better suited to protect us and help us survive.

Both our genetics and environments are enormous categories made up of millions of factors. In the genetics category, we have variants, inherited mutations, and gene expression. In the environment category (referred throughout as “social factors”), we have childhood experiences, education, and culture. Here, we’ll focus on a factor in the environment category – our relationships. And fittingly, it’s a bit complicated…

Evidence suggests that healthy, strong relationships promote better health outcomes, while difficult relationships or recurring relationship struggles are linked to poorer ones. This connection can be explained by the companionship, shared resources, social interaction, and emotional support we receive and give in our relationships. These “feel good” elements can make it easier to care for ourselves and motivate us to do the same for the people we love. In turn, we sleep peacefully, stress less, celebrate more, and make sure our partners go to the dentist every six months. This goes beyond just romantic relationships, encompassing our relationships with our family, chosen family, friends, co-workers, neighbors, and pets.

Applying the nature vs. nurture debate to relationships, which parts of our genetics and environments are holding the baton in the relay race? In a recent study, researchers sought to find associations between certain genetic predispositions, social factors, and marriage patterns. The results don’t resolve the nature vs. nurture debate, but they do offer a compelling view on how these forces dynamically shape our relationships and, in turn, our health.

Before diving in, it’s important to acknowledge a key limitation of this study. The primary analyses focused on non-Hispanic white participants. As a result, the findings do not fully reflect the diversity of people, identities, and relationships that exist in the real world.

Participants were grouped into 6 categories: married by 20, married in their 20s, widowed, remarried, divorced, and never married. Researchers then compared each group’s genetic profiles and social factors, both separately and together.

To study genetic influences on traits that aren’t simply observed or confirmed by diagnostic testing, researchers use polygenic scores (PGS), measures of an individual’s genetic predisposition for a given trait or condition. These scores are calculated by comparing an individual’s combination of genetic variants – a change in the DNA sequence – to the genetic variants commonly found in groups of people known to share a trait. For example, individuals who experience certain signs of depression may share a higher frequency of specific genetic variants. Researchers can then estimate someone’s individual risk for depression by comparing their genetic profile to that group. It’s a bit like how a meteorologist uses changes in air pressure and wind patterns to forecast a storm.

PGSs were determined for educational attainment, wellbeing, depression, and body mass index (BMI). The most clear correlation emerged around the educational PGS – a higher educational PGS was linked to a lower likelihood of marrying by 20 or remarrying. When separated by gender, this pattern became even stronger, showing an additional association between educational PGS and divorce among women. Men with higher educational PGSs were less likely to remarry. All together, participants genetically predisposed to higher educational attainment tended to experience fewer early or disrupted marriages.

Associations for the other PGSs were limited and specific to men. Men with higher wellbeing PGSs were less likely to remain unmarried, while those with higher depressive and BMI PGSs were more likely to be married by 20.

I’d be remiss not to highlight a striking finding from the analysis of social factors (including education and socioeconomic status): although women and men reported similar overall health outcomes, women typically scored higher for depressive symptoms. This may reflect the caretaking burden that women often take on in marriages. Cue Femininomenon by Chappel Roan!

Researchers analyzed the marriage patterns with the PGSs, the social factors, and both combined. Results were very similar for the analysis of social factors alone and with PGS and social factors combined. In this relay, nurture takes the baton.

What makes this research particularly distinctive is that it looks at the real-world consequences of genetics. It takes an extra step past just identifying variants and asks what they mean for lived experience. You might attract a partner based on your bright blue eyes and your drive in school (a high educational attainment PGS). Maybe your type is tall with a sense of adventure (a low depressive PGS). That’s your prerogative – and of course, that is influenced by your genetics, too.

In the end, genetics affect our behaviors, behaviors shape our relationships, and our relationships impact our health. The pickup lines may be written in our DNA but the connection grows with our lived experiences.

Edited by Ethan Honeycutt and Jameson Blount