Nature vs. nurture results in a draw, according to twins meta-study

Nature vs. nurture results in a draw, according to twins meta-study
The research drew on data from almost every twin study across the world from the past 50 years.

One of the great tussles of science – whether our health is governed by nature or nurture – has been settled, and it is effectively a draw.

University of Queensland researcher Dr Beben Benyamin from the Queensland Brain Institute collaborated with researchers at VU University of Amsterdam to review almost every twin study across the world from the past 50 years, involving more than 14.5 million twin pairs.

The findings, published in Nature Genetics, reveal on average the variation for human traits and diseases is 49 per cent genetic, and 51 per cent due to and/or measurement errors.

"There has still been conjecture over how much variation is caused by genetics and how much is caused by environmental factors—what people call nature versus nurture," Dr Benyamin said.

"We wanted to resolve that by revisiting almost all the genetic twin studies conducted over the past 50 years, and comparing all of them together," he said.

Although the contribution of genetic and environmental factors was balanced for most of the traits studied, the research showed there could be significant differences in individual traits.

For example, risk for bipolar disorder was about 70 per cent due to genetics and 30 per cent due to environmental factors.

"When visiting the nature versus nurture debate, there is overwhelming evidence that both genetic and environmental factors can influence traits and diseases," Dr Benyamin said.

"What is comforting is that, on average, about 50 per cent of individual differences are genetic and 50 per cent are environmental.

"The findings show that we need to look at ourselves outside of a view of , and instead look at it as ."

In 69 per cent of cases, the study also revealed that individual traits were the product of the cumulative effect of genetic differences.

"This means that there are good reasons to study the biology of human traits, and that the combined effect of many genes on a trait is simply the sum of the effect of each individual gene," Dr Benyamin said.

"This finding has implications for choosing the best strategy to find genes affecting disease."

Professor Peter Visscher from QBI said the study was performed using publications from the classical twin design, which compares the similarities of identical twins who share all their genes, to those of non-identical twins who share 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," Professor Visscher said.

The study involved a meta-analysis of 17,804 traits from 2748 publications between1958 and 2012, based on data from 14,558,903 . The paper is online here.

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More information: "Meta-analysis of the heritability of human traits based on fifty years of twin studies." Nature Genetics (2015) DOI: 10.1038/ng.3285
Provided by University of Queensland
Citation: Nature vs. nurture results in a draw, according to twins meta-study (2015, May 19) retrieved 22 February 2019 from
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May 19, 2015
From Fertilization to Adult Sexual Behavior
Authors: Milton Diamond Ph.D., Teresa Binstock, and James V. Kohl
Published in: Hormones and Behaviour, 30, 333-353 (1996)

RNA-mediated cell type differentiation links the epigenetic landscape to the physical landscape of DNA via nutrient-dependent metabolic networks and genetic networks. Nutrient-dependent ecological variation leads from RNA-directed DNA methylation and RNA-mediated amino acid substitutions to cell type differentiation in all cells of all individuals of all genera.

First author, Milton Diamond subsequently exposed the textbook "fraud" exemplified in the John/Joan nature/nurture case. See: Sex reassignment at birth: Long-term review and clinical implications

See also: and

May 19, 2015
The cultural environment is very similar between twins in these studies when we consider the full possible range of environmental conditions.

For instance contrast Hunter-gatherer, medieval peasant and modern western.
Even within the modern environment we have variation such as Pakistani village Muslim, wealthy Saudi Arabian, Modern Western and so on.

In twin studies, the cultural environment is almost always held constant, so eliminating a huge chunk of environmental or 'Nature' variation.

Cultural environmental conditions contribute around 25~33% of variation, but this does not appear if the environments are not sufficiently diverse. Two variations of modern western culture represent only very modest variation when contrasted with the possible range. City vs farm would be close to the middle of the range.

May 20, 2015
See also: http://www.the-sc...esults-/

It should be perfectly clear that most evolutionary theorists will not accept factual representations of biologically-based cause and effect.

Also, it should be perfectly clear that RobertKarlStonjek has decided to change his misrepresentations of biologically-based cause and effect to make them consistent with what has been known to serious scientists since Dobzhansky (1973). See his comments on this news report, as moderator of the Evolutionary Psychology News FB group at https://www.faceb...chNews/.

Excerpt: the variables the need to be understood before a prediction of a persons response to a stimuli can be predicted are:
* The person's genetic predisposition;
* Their maturation environment;
* The history of the interaction between the individual and the environment...
See also https://www.faceb...ediated/

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