NORWICH, UK — Charles Darwin’s theory of natural selection is put to the test. Darwin’s theory explained that organisms that can better adapt to their environment are more likely to survive and produce more offspring. However, a new study by British researchers reveals that natural selection could make society more unequal.
Researchers from the University of East Anglia have found that natural selection favors poorer, less educated people. The study “shows how the effects of natural selection are stronger in lower-income and less-educated groups, in younger parents, in people not living with a partner, and in people with more lifelong sexual partners.”
On the other hand, natural selection “opposes the genes” associated with highly educated people, people with higher lifetime incomes, those at low risk of ADHD or major depressive disorder, and those who have a lower risk of coronary heart disease.
“Darwin’s theory of evolution asserted that all species developed by natural selection of small heritable variations that increased the individual’s ability to compete, survive and reproduce,” says lead researcher David Hugh- Jones, a professor at the UEA School of Economics, in a university outing. “We wanted to know more about the characteristics selected for and against in contemporary humans living in the UK.”
Do ‘polygenic scores’ prove that Darwin’s theory of natural selection is no longer valid?
The researchers analyzed the polygenic scores of more than 300,000 people in the UK, taken from the UK Biobank, which is a long-term project studying the contributions of genetic predisposition and environmental exposure to disease development. Polygenic scores estimate a person’s genetic responsibility, a prediction of their health, upbringing, lifestyle, or personality.
The researchers then used data on two generations of people living in the UK by looking at their number of siblings and the number of children.
“We found that 23 out of 33 polygenic scores were significantly related to whether a person had more or fewer children in their lifetime,” says Hugh-Jones. “Scores correlated with lower income and education predicted having more children, meaning these scores are selected from an evolutionary perspective.”
Meanwhile, researchers say scores correlated to those with higher incomes and better education predict having fewer children, “meaning they’re selected against.”
“Natural selection could make society more unequal, by increasing the correlation between income and polygenic scores, including scores that predict health and education outcomes,” the study’s author continues.
Using the economic theory of fertility, researchers argue that those with higher incomes can afford to have more children. However, since it is expensive to spend time caring for children instead of working, they will lose higher wages.
“The first effect leads people to have more children, the second effect leads them to have fewer,” concludes Hugh-Jones.
The study is published in the journal Behavioral genetics.