In a world-first study, QBI researchers have discovered that epistasis, the interactive effect of two or more genetic mutations in the genome, influences the expression of genes in human populations.

Working with scientists at UQ’s Diamantina Institute, the team found that epistasis – the long debated effect of whether mutations interact with each other – exists throughout human populations.

This could be applied when treating diseases including Alzheimer’s, after 16 independent pairs of polymorphisms were shown to have an epistatic effect on the expression levels of TRAPPC5, a gene known to be involved in the disease.

This new information can be used by other researchers to investigate the functional role that these interacting mutations have on susceptibility to developing Alzheimer’s.

Senior author of the study, Dr Joseph Powell, said that the study detected hundreds of pairs of common, natural polymorphisms in humans that exhibit epistasis.

“These polymorphisms were shown to have an effect on the levels of gene expression,” Dr Powell said.

“No one really knew how prevalent it was.

“There has been a huge discussion in the community about how common these types of genetic effects are and how much of the genetic variation was caused by them.

“Epistasis has been shown in model organisms, but the genetic variations have been artificially created.”

The findings open up further research into understanding how mutations are carried within the population, which can impact disease susceptibility knowledge.

The study, “Detection and replication of epistasis influencing transcription in humans”, was published in Nature.