Researchers at Ben-Gurion University of the Negev, Israel have discovered a unique set of indicators that help identify the genes associated with autism.
Dr Idan Menashe and his colleagues, Mr Erez Tsur and Professor Michael Friger, studied the sequences of 651 genes that are associated with autism and discovered characteristics that distinguish them from other genes in the genome. Their study is published in the journal Behavior Genetics.
Among the distinct characteristics of autism genes is their exceptional genomic length, which is even longer than other brain-expressed genes of closely related diseases such as Alzheimer’s disease and schizophrenia.
The authors also found a unique genomic signature in these genes that was shaped by negative selection, an evolutionary process that removes disruptive mutations from genes over generations.
Menashe and his colleagues also searched for evidence of positive selection in these genes as this could explain the presence of autism in the human population. However, no indications of positive selection acting on autism genes were found. This suggests autism susceptibility mutations are maintained in the human genome probably because they cause the disorder only in combination with other genetic and/or non-genetic factors.
The authors used the unique characteristics of autism genes to identify additional candidate genes for the disorder, demonstrating that this evolutionary ‘signature’ is highly efficient in capturing well-established autism genes.
The study concludes:
Our findings suggest that ASD genes have evolved under complex evolutionary forces, which have left a unique signature that can be used to identify new candidate ASD genes.