Left-handedness is genetic

Scientists finally identify its genetic components

| THE INDEPENDENT | For the first time, scientists have pinpointed regions of human DNA that closely relate to whether people are right- or left-handed. They also linked these regions to language-related features in the brain.

Previously, scientists knew that genes were responsible for around 25% of handedness.

However, before the emergence of new research from the University of Oxford, in the United Kingdom, it was not clear which genes were involved.

A recent paper about the new study appears in the journal `Brain’.

The authors describe how they found the DNA regions after analysing the genomes of around 400,000 UK Biobank participants, including more than 38,000 who said that they were left-handed.

The study is the first to relate specific areas of the genome to handedness in the general population.

“Around 90% of people are right-handed,” says first study author Dr. Akira Wiberg, a Medical Research Council fellow at the University of Oxford, “and this has been the case for at least 10,000 years.”

Genetic regions linked to brain development proteins

In their genetic analysis, the researchers identified four DNA regions that related strongly to handedness.

Three of the regions are either within or influence genes that code for proteins that are “involved in brain development and patterning.”

These proteins have a key role in making scaffolding-like building blocks called microtubules that guide the construction of cells.

Comprising long-chained molecules, microtubules make up the cytoskeleton, or the physical structure of cells throughout the body, and can assemble and disassemble very quickly in response to cell signals.

The genes that drive the formation of the cytoskeleton are also responsible for right and left differences in growth and development in animals. This can appear, for example, in snails whose shells can coil either to the left or the right.

Microtubules also maintain the transport infrastructure that enzymes use to carry cargo around different parts of the cell.