Australasian Science: Australia's authority on science since 1938

Wasp Gene Link to Autism, Schizophrenia

Image of wasp

The NRXN1 gene exists in three species of Nasonia wasps.

By Stephen Luntz

Genes believed to be implicated in autism and schizophrenia have been found in the sequencing of the genome of three species of parasitic wasp, indicating they are extraordinarily ancient and essential for animal survival.

The protein neurexin 1 is linked to learning in species as diverse as mice, humans and honeybees. Defects in the protein are common in families where autism and impaired social interactions are common.

Bee brains are flooded with neurexin 1 when they learn to associate odours with food. The protein helps form connections between neighbouring neurons, providing the linkage essential to the operation of learning in the brain.

The Queensland Brain Institute (QBI) has demonstrated that the NRXN1 gene exists in three species of Nasonia wasps. The previous discovery of the gene in flies and bees demonstrated that it must be very ancient, but its presence in insects smaller than a pinhead reveals its widespread evolutionary conservation.

“Together these organisms provide important new tools for studying the molecular basis of brain function. Using these insect models, we can now examine the role of genes involved in connecting neurons in the brain,” says QBI researcher Dr Alexandre Cristino.

The QBI team also identified the gene responsible for the neuroligin protein, whose variations are also believed to contribute to autism and schizophrenia.

Team leader Dr Charles Claudianos says there are reasons besides the contribution to neuroscience to study the Nasonia wasps. “There are over 600,000 species of these parasitoids in nature that can be used in biological control of agricultural pests and insects that transmit disease. Despite their critical role in providing natural control of many pests, most people are unaware of these helpful insects.”

Another outcome of the genome sequencing was the discovery of DNA methylation in wasps, where genes are turned on and off by environmental factors. “This is the first time that DNA methylation has been shown to work in a non-social insect,” says Prof Ryszard Maleszka. “By understanding more about how methylation works in a relatively simple creature like Nasonia wasps, we can learn more about how it works in humans, where the process is turning out to be important in a range of conditions such as cancer, obesity and mental illness.”