A person's genes can partly predict their likelihood of success in life, according to a new study.
Many previous studies have found correlations between indicators of 'success' such as education level, wealth and income and particular genetic markers. However, it is difficult to separate the influence of genes from that of the environment. For example, educational and income success could be a result of the parents' social class.
In this current study, published in PNAS, the researchers aimed to control for these environmental effects in order to find out the input that genes have.
They used data from five longitudinal studies (studies tracking the same people over many years) in the UK, the USA and New Zealand, and assessed factors such as occupation, education and wealth in more than 20,000 people.
Lead study author Dr Daniel Belsky at Duke University in Durham, North Carolina, told Newsweek: 'There are now hundreds of individual variations throughout the genome that are roughly associated with educational outcomes between people.'
The team used such genetic variations to generate a 'polygenic score' for an individual, which is a number based on possession of genetic markers which are thought, based on previous studies, to be associated with educational and other success.
They found, not unexpectedly, that people with higher polygenic scores tended to have grown up in wealthier families, and with better educated parents. However, when controlling for these factors, they found that individuals were more likely to achieve upward mobility compared with their parents in terms of occupation, wealth, social position and education level if they had a higher polygenic score.
'Even though kids born into better-off families did tend to have slightly higher polygenic scores, higher scores predicted success no matter what kind of conditions a child grew up in,' Dr Belsky told Harvard Business Review.
Another way in which the researchers attempted to control potential confounding factors was by comparing siblings - specifically non-identical twins – directly, with the reasoning that twins would have a similar upbringing and social class. They found that the twin with the higher polygenic score was more likely to achieve greater success in later life.
Other comparisons showed that higher polygenic scores for mothers predicted higher educational attainment for her children, even when controlling for the child's own polygenic score.
The authors say that their results show that genetic correlation with success is not a coincidence. However, they pointed out that these differences still explained only a small amount of variation in social mobility.
'There's nothing in our study that says these genetic variants are a more powerful predictor of outcomes than family backgrounds,' said Dr Belsky.