The age-old nature versus nurture question has spewed countless debates throughout history. But now, Australian researchers say they have the answer and, well, it’s a draw, folks.
Based on a study published in Nature Genetics, human traits are determined almost equally by both nature and nurture.
The researchers collated 2,748 twin studies from the last 50 years and found that 49 percent of the average variation for human traits and diseases was down to genetics, and the other 51 percent was due to environmental factors.
University of Queensland researcher Dr Beben Benyamin from the Queensland Brain Institute teamed up with researchers at VU University of Amsterdam to review the five decades of studies.
“Twin studies have been conducted for more than 50 years, but there is still some debate in terms of how much the variation is due to genetic or environmental factors,” Benyamin told the Guardian.
Benyamin added that the study proved that the conversation should move away from nature versus nurture and instead be focused on how they can work together.
“When visiting the nature versus nurture debate, there is overwhelming evidence that both genetic and environmental factors can influence traits and diseases,” said Benyamin.
“What is comforting is that, on average, about 50 percent of individual differences are genetic and 50 percent are environmental.
“The findings show that we need to look at ourselves outside of a view of nature versus nurture, and instead look at it as nature and nurture.”
The study, which involved more than 14.5 million sets of twins worldwide, compared the similarities of identical twins who share the same genetic makeup with those of non-identical twins who share only half their genes.
“Twin studies have been the main method for researching the genetic and environmental sources of variation between humans for a long time because of the availability of the two types of twins,” said fellow Queensland Brain Institute researcher Professor Peter Visscher.
While it was concluded that there was an almost 50/50 split between the effects of nature and nurture, the 17,804 separate characteristics looked at in the study showed major variations in individual traits.
For instance, the risk for bipolar disorder was found to be 68 percent due to genetics and 32 per cent due to environmental factors. And weight maintenance was 63 percent due to genetics and 37 percent due to environmental factors. However, the risk of developing eating disorders was found to be 60 percent environmental and 40 percent genetic.
Benyamin told the Guardian that although mental disorders and skeletal traits had a greater genetic influence than environmental factors, the environment does play a larger role in attitudes and social values.
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