Researchers at Oxford University find gene for left-handedness
An international group of scientists, led by a team from the Wellcome Trust Centre for Human Genetics at the University of Oxford, have discovered a gene that increases the chance of being left handed. The study is published on-line today by the journal Molecular Psychiatry.
The research, which involved over 40 scientists from 20 research centres around the world, revealed a gene called LRRTM1; the first to be discovered which has an effect on handedness. Although little is known about LRRTM1, the Oxford team suspects that it modifies the development of asymmetry in the human brain. Asymmetry is an important feature of the human brain, with the left side usually controlling speech and language, and the right side controlling emotion. In left-handers this pattern is often reversed. There is also evidence that asymmetry of the brain was an important feature during human evolution; the brains of our closest relatives, the apes, are more symmetrical than humans' and they do not show a strong handedness.
The Left-Handers Club welcome these new findings, as a genetic link has long been considered the most likely cause of left-handedness yet a specific gene has until now remained elusive. This is the first potential genetic influence on human handedness to be identified, and the first putative genetic effect on variability in human brain asymmetry. LRRTM1 is a candidate gene for involvement in several common neurodevelopmental disorders, and may have played a role in human cognitive and behavioral evolution.
The researchers also discovered that LRRTM1 might slightly increase the risk of developing schizophrenia. People with schizophrenia often have unusual patterns of brain asymmetry and handedness, so the researchers were not surprised when LRRTM1 also showed a possible effect on the risk of developing schizophrenia. Schizophrenia is a disorder of the brain which results in impaired perception and thought. It affects roughly one percent of adults worldwide.
There has not, however, been any assumption that left-handedness and schzophrenia are linked. The study leader, Dr Clyde Francks, said: "People really should not be concerned by this result. There are many factors which make individuals more likely to develop schizophrenia and the vast majority of left-handers will never develop a problem. We don't yet know the precise role of this gene."
Some of the researchers involved in this discovery are now planning further study on the roles of LRRTM1 in the developing brain, and to find other genes with which LRRTM1 interacts. Dr Francks said: "We hope this study's findings will help us to understand the development of asymmetry in the brain. Asymmetry is a fundamental feature of the human brain that is disrupted in many psychiatric conditions."
For more information contact:
Dr Clyde Francks (Study Leader)
GlaxoSmithKline
Email: clyde.2.francks (at) gsk.com
Phone:
Prof Anthony Monaco (Laboratory Head)
Wellcome Trust Centre for Human Genetics University of Oxford
Email: anthony.monaco (at) well.ox.ac.uk
Phone: 302 945 5349
See
www.well.ox.ac.uk/~clyde/index.shtml
