The wide-ranging influence of genetics
The Left long denied the influence of genetics but now simply ignore it. The study below is therefore powerful evidence of just how wrong they are. Hans Eysenck, a considerable student of genetics, once said to me, "It's ALL genetic". He was of course making a conversational statement to a colleague rather than a precise scientific one but the present study does confirm one sense of what he said: ALL traits have a substantial genetic component. And the writer below makes the correct and important point that the 50/50 split observed is only an average and that the genetic contribution varies from trait to trait. So the findings do not overturn the usual finding that IQ is about two thirds genetic
It's a question that dogged scientists for close to a century and Queensland researchers say they have the answer. When it comes to health, in the age-old battle of nature versus nurture… It's a draw.
University of Queensland research fellow Dr Beben Benyamin worked with scholars at the VU University of Amsterdam to review almost every twin study completed globally in the past 50 years.
After analysing studies of more than 14.5 million twin pairs across 17,804 traits from 2748 publications, they found variation for human traits and diseases was 49 per cent genetic (nature), and 51 per cent due to environmental factors (nurture).
The Queensland Brain Institute researcher said the draw was expected but he was pleased to be able to put a number on the variation and surprised by how similar an influence each aspect had.
"Most of the reviews have been for specific traits, like people are interested in studying one particular disease and review all the twin studies for one disease," he said. "But this is I think is the first one to review everything about all disease and all twin studies that are available at the moment."
The influence of nature and nurture is actually a complex interplay rather than a simple either/or and is far from equal across all traits and diseases.
The risk for bipolar disorder was about 70 per cent due to genetics and 30 per cent due to environmental factors, Dr Benyamin found.
Posted by John J. Ray (M.A.; Ph.D.).