Oxford research finds genetic cause of handedness in humans

Scientists at Oxford, St Andrews, Bristol and The Max Plank Institute in Nijmegen, have identified a link between a network of genes, whose role is to influence growth of young embryos, and the characteristic known as left or right handedness.

Handedness has been a social and cultural issue for thousands of years, with 70-95% of people being right handed globally according to Scientific America. There has even been a degree of historical persecution of left-handers, which still leaves many derogatory terms floating around today, such as “cack handed”.

The genes responsible for influencing handedness are the same ones, which effect how an embryo develops from a ball of cells, into a living thing with a left and right side.

This in turn influences left right dominance in the brain, which has a knock on effect on the predominant use of the left or right hand.

The team of scientists conducted a genome wide study, to find an association between gene variance and the degree of left/right handedness in the sample.

The gene that had the most statistically significant correlation in the study is known as PCSK6. The results of the study have been published in PLOS Genetics, which is an open access journal.

This gene when knocked out in mice can lead to the misplacement of organs, i.e. a stomach can grow on the right and the liver on the left.

However William Brandler a PhD student at Merton College, who has been working on the project, cautions that this study does not provide the whole story as to why handedness is such a common trait among humans.

Brandler states “handedness is a behavioural trait controlled by the interplay between hundreds of genes and environmental factors such as a cultural pressure to conform to societal norms. Understanding the full genetic mechanism will require massive sample sizes of hundreds of thousands, possibly millions of participants, and we do not have the resources yet to do this”.

However he still maintains the significance of the findings by stating “these findings are important because we want to understand how the brain develops at a molecular level. Since handedness is an outward reflection of brain asymmetry, this is an easy way of gaining insight into this question. We’ve identified not only genes, but an entire biological mechanism that plays a key role in handedness, and therefore brain asymmetry”.