After years of discussion, scientists finally seem to have found the answer to what determines our behaviour: genetics or environmental factors. Apparently, no clear distinction can be made between the two, because both contribute equally. This simultaneously implies that every trait is hereditary, in contrast to previous assumptions. The VU Amsterdam and the University of Queensland, Brisbane, presented the results of the largest twin study yet in Nature Genetics.
The research was conducted by analysing data from 14.5 million twin pairs, originating from articles published between 1958 and 2012. With this tremendous amount of information the scientists could determine the genetic and environmental component of hundreds of human traits. Psychiatric, metabolic and cognitive features of twins were particularly well-documented in these studies.
“Taken together, the average contribution of heredity is 49 percent and environmental factors account for 51 percent”, says one of the authors, Daniëlle Posthuma, professor of neurosciences at the VUmc Amsterdam. This is also applicable to traits like anti-social behaviour, which previously have been ascribed to bad parenting. According to the authors, their study results will stimulate other researchers to further assess the hereditary components of such behavioural traits.
The scientists expect their elaborate meta-analysis will form a new touchstone in genetics. “New studies should preferably focus on features not extensively analysed yet, like multiple sclerosis, epilepsy or Parkinson’s disease. We expect our results to become an important reference point for future research on heredity”, says Posthuma.
Sources: VUmc, Nature Genetics
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