Sep. 12, 2013 — A genetic study has identified a biological
process that influences whether we are right handed or left
handed.
Scientists at the Universities of Oxford,
St Andrews, Bristol and the Max Plank
Institute in Nijmegen, the Netherlands,
found correlations between handedness
and a network of genes involved in
establishing left-right asymmetry in
developing embryos.
'The genes are involved in the biological
process through which an early embryo
moves on from being a round ball of cells
and becomes a growing organism with
an established left and right side,'
explained first author William Brandler, a PhD student in the MRC
Functional Genomics Unit at Oxford University.
The researchers suggest that the genes may also help establish
left-right differences in the brain, which in turn influences
handedness.
They report their findings in the open-access journal PLOS
Genetics.
Humans are the only species to show such a strong bias in
handedness, with around 90% of people being right-handed. The
cause of this bias remains largely a mystery.
The researchers, led by Dr Silvia Paracchini at the University of St
Andrews, were interested in understanding which genes might
have an influence on handedness, in order to gain an insight into
the causes and evolution of handedness.
The team carried out a genome-wide association study to identify
any common gene variants that might correlate with which hand
people prefer using.
The most strongly associated, statistically significant variant with
handedness is located in the gene PCSK6 , which is involved in the
early establishment of left and right in the growing embryo.
The researchers then made full use of knowledge from previous
studies of what PCSK6 and similar genes do in mice to reveal
more about the biological processes involved.
Disrupting PCSK6 in mice causes 'left-right asymmetry' defects,
such as abnormal positioning of organs in the body. They might
have a heart and stomach on the right and their liver on the left,
for example.
The researchers found that variants in other genes known to
cause left-right defects when disrupted in mice were more likely
to be associated with relative hand skill than you would expect by
chance.
While the team has identified a role for genes involved in
establishing left from right in embryo development, William
Brandler cautioned that these results do not completely explain
the variation in handedness seen among humans. He said: 'As
with all aspects of human behaviour, nature and nurture go hand-
in-hand. The development of handedness derives from a mixture
of genes, environment, and cultural pressure to conform to right-
handedness.'
wow! nice !
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