Genes may influence your successes and failures in life

DNA sequencing graph

Many of us like to think if we work hard, we’ll succeed. But what if there’s something we have no control over that could influence how successful we are?

Recent research suggests our genes can influence how far we go in school and how much money we make as adults.

Kathryn Paige Harden, a professor of psychology and behaviour geneticist from the University of Texas, says acknowledging “genetic luck” could be used to help create a more equitable society.

However, her book on the subject, The Genetic Lottery: Why DNA Matters for Social Equality, has caused considerable debate, with some even calling it “dangerous”.

Professor Harden understands the criticism. She says the history of the genetic sciences and the “atrocious eugenic views” held by many of the field’s forefathers make it a difficult field to navigate.

“There has never been a time, from Darwin on, in which the discussion of genetics or evolution or heredity in relation to humans has not been something that causes anxiety and controversy,” she says.

Black and white portrait of a bald man with grey sideburns, wearing a black suit and tie.
Francis Galton, who coined the term eugenics in the late 1800s, is part of the dark history of the genetic sciences. (Getty Images: Hulton Archive/Stringer)

However, she argues it’s time to “reclaim” the field and embrace the idea that, although they may not fully determine our destiny, our genes do matter.

‘Sceptical it would work’

Until the commencement of the international scientific research project, the Human Genome Project (HGP), in 1990, there was little understanding of what humans looked like on a molecular level. This meant looking at our genetic similarities and differences was next to impossible.

By 2003, when the HGP wrapped up, researchers had successfully mapped over 90 per cent of the human genome. And in March 2022, the final pieces of the human genome puzzle were put in place.

Theoretically, there is now a set of instructions for how to build a human being.

“Every human has in their cells 23 pairs of chromosomes, unless you have a condition like [Down syndrome], in which you’ve inherited an extra chromosome,” Professor Harden says.

“All these chromosomes, your DNA, are made up of four DNA letters: G, C, T and A.

“Humans are more than 99 per cent genetically similar,” Professor Harden says, adding that “most of what human DNA does is make a human body”.

It’s the remaining portion – less than 1 per cent – that differs between people that scientists like Professor Harden are interested in.

She says most studies focus on the single DNA letter differences between people known as single-nucleotide polymorphisms orSNPs, which are the most common type of genetic variation found among people.

“I might have a T in a certain spot, and you might have a C in a certain spot,” she says.

“[There can be] millions of [these genetic variants] scattered throughout your entire genome.”

Around two decades ago, scientists began to look at which SNPs were associated with specific outcomes.

“[For instance] if the outcome we are interested in is height, we might say which genetic variants (SNPs) are more common in tall people versus short people,” Professor Harden says.

Initially these studies focused on things like high cholesterol, macular degeneration or type 2 diabetes.

This research has helped identify genetic variants associated with an increased susceptibility to developing these conditions later in life.

But since then, the focus of these studies has shifted.

Researchers are now looking at more socially focused outcomes, such as how far someone went in school, how much money they make and if they’ve ever been addicted to opiate drugs.

“A lot of people were sceptical that [this research] would work,” Professor Harden says.

However, studies show patterns of genetic correlations that are related to these psychological behavioural outcomes.

Genes and personality

When it comes to how well kids and adolescents do in school, Professor Harden says we already know all things aren’t equal.

“We have a ton of research about that from educational and developmental psychology,” she says.

We know that poverty and disadvantage outside of school impact students’ educational outcomes. 

But Professor Harden argues that cognitive ability is another part of the equation. 

“If you have better working memory, better visual spatial reasoning [or] a stronger vocabulary, school is easier for you,” she says.

Non-cognitive factors also come into it. One of those is personality, something that Professor Harden is very interested in.

“There are personality traits that might make school easier or harder,” she says.

Things like impulsivity, how organised you are and how persistent you are. And these traits are at least partly shaped by our genes, she says.

The back of a boy with blonde hair sitting at a school desk going over his work.
Professor Harden says a 2022 study found thousands of genetic variants that were more or less common in people who had gone further in school. (Getty Images: Sydney Bourne)

The relationship between genetics and educational and economic success is complex. Professor Harden says people often try to simplify it by comparing it to a poker game.

“There’s the genes or the hand you get dealt, but there’s still how you play that hand,” she says.

But the effect of genes on things like personality means this metaphor can break down.

“Our genes are also influencing how we play the hand we’re dealt. It influences how motivated we are, how [much we plan], how much impulse control we have,” she says.

“It makes this line between what’s effort and agency and what’s [genetic] luck kind of impossible to tease apart.”

Diversifying genetics

Professor Harden says there’s a problematic lack of diversity in the research so far on this topic.

A woman with blonde hair and a black dress looks at the camera.
Professor Harden says we need to recognise the power of DNA to help create a more just society. (Supplied)

“Right now, the vast majority of information we have about the human genome comes from one narrow slice of the global population and that’s people with Northern European ancestry,” she says.

“The most common study is of people who self-identify as white British.”

She argues that this isn’t only “inequitable” but it “hurts the science”.

“We’re neglecting an enormous pool of genetic diversity and variety,” Professor Harden says.

She believes expanding the diversity of genetics is a great opportunity for future work in the field. But in the meantime, we’re left with studies that don’t necessarily apply to everyone.

‘People are hungry for new tools and solutions’

Given genes are immutable, Professor Harden says a lot of people have asked why the recent studies matter so much.

She says this is because there is scope to intervene and make a difference.

“Just because something is genetic doesn’t mean we can’t intervene on it environmentally.”

One example she highlights is how family therapy is used to help treat alcohol abuse problems in adolescents.

“[Genetically speaking], not every teenager is equally likely to develop an alcohol abuse problem. Some of that genetics has to do with how your body metabolises alcohol, but some of it has to do with personality,” she says.

“Do you tend to like loud, rowdy friends? Do you like to go to parties where substances will be on offer?”

Professor Harden says randomised controlled trials have shown that family therapy, which aims to improve parent-teenager relationships and communication, is an effective treatment and helps kids who are “most genetically at risk”.

“That’s because one of the pathways between their genetic risk and their addiction is through their social environment.”

The possibility of making a difference is posed as a question in Professor Harden’s book.

“How can public spaces, working conditions, access to medical care and legal codes and social norms be reimagined such that the arbitrariness of nature is not crystallised into an inflexible caste system?” she writes.

And some people are looking for the answers.

Professor Harden says although there’s been a bit of “pushback” from fellow academics, there’s also been a lot of interest from policymakers and governmental institutions

“[They] have reached out to me to say: ‘We want to hear more about this’. I think a lot of people are hungry for new tools and new solutions.”

This conversation between Rob Brook and Kathryn Paige Harden was originally recorded as part of UNSW Centre for Ideas and broadcast on ABC RN’s Big Ideas.

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