Genetic interaction occurs when two or more mutations in genes interact to produce an unexpected characteristic - with one affecting the other. For example, two mutations, that would not be lethal by themselves, can combine to cause the death of a cell. But the process by which genes and their mutations interact with each other is complex – as some are more likely to interact than others. Now researchers from the University of Toronto have created the world's first map that shows how genes in a cell interact. Now researchers from the University of Toronto created the world's first map that shows how genes in a cell interact.