Genes that are beneficial in the female may cause a predisposition to autism in the male, according to the preliminary findings of a new research study at University College Cork (UCC).
Senior lecturer at the department of biochemistry, UCC, Dr Tom Moore said such genes were "sexually antagonistic" as a gene variant that was beneficial in one sex may be harmful to the other.
His research has found evidence of sexually antagonistic genes in the context of autism - gene variants that may be beneficial to a female may cause autism in a male.
"Autism is a serious neurological disorder that may be increasing in frequency. Our current understanding of the causes of autism, which predominantly affects boys, suggests that the disorder is predominantly genetic in origin," said Dr Moore.
However, the lack of progress in identifying major susceptibility genes suggests that autism is a very complex disorder and environmental influences on the condition cannot be ruled out, he said.
Dr Moore points out that in the case of identical twins, both children have the disorder in only 50-60 per cent of cases and not in all cases, which means there must be some other non-genetic contributors to the condition.
"Autism is a complex disorder and the tools for mapping genes for diseases perform quite poorly for disorders where there is more than one or a handful of genes involved which is probably the case with autism," he said.
"Estimates vary wildly, we know there are more than five genes involved, but we do not know how high this figure goes."
Dr Moore said there was still very little understood about the condition and its causes and while progress has been made, he believes it will be slow and steady rather than any major breakthrough happening overnight.
His own work involves looking at gene variants which may be good for individuals in some situations and bad for others. For example, in cystic fibrosis the normal variant of a "good" gene mutates into a "bad" variant which causes the disorder.
Through his investigation of two genes on the tips of the Y and X chromosomes, Dr Moore has found some evidence that the genes are involved in autism and subject to a type of antagonistic selection.
While sexually antagonistic genes have been well described in studies of the fruit-fly, for example, he believes this is the first time they have been implicated in human genetic disease.
"Genes can be pulled in two directions by natural or sexual selection.
"It would be nice if all the genes that were good for the male were on the Y chromosome which is found only in males and all those that were good for women were found on the X chromosome, but the genome is far too big," he explained.
Dr Moore, who is running a programme funded by the Higher Education Authority (HEA) in integrative reproduction, stressed that his findings were preliminary and had not yet been subject to peer review, although they would be published shortly.
He will speak on the topic of Autism and the Battle of the Sexesin the next of the Faculty of Science public lecture series at UCC which takes place tomorrow night at the Boole lecture theatre at 8pm.
Admission to the lecture is free and the public is invited to attend.
