Imagine that sexual reproduction could occur between hyphae that were the same mating type. How might this affect rates of evolution in fungi? Rates of evolution would increase, because more novel genetic combinations are generated through sexual reproduction. Rates of evolution would stay the same, because as long as sexual reproduction is occurring, it does not matter whether it is between individuals of the same or different mating type. Rates of evolution would decrease, because genetic variation would reduce.

Reduce the rate of evolution

Explanation:

Sexual reproduction is the mode at which living organisms produce variation in species. This is important for phenotypic plasticity, adaptation, evolution and preservation of a species. The crux of sexual reproduction is to allow the exchange of genetic material between two genetically diverse individuals to produce offspring that are genetically diverse from both parents and the individuals in its clutch. Whenever sexual recombination occurs between hyphae of the same mating type there is no variation in genetic information and therefore no opportunity for variation. Unless there are external factors that influences gene sequences there will be few to no chances for variation. This reduces the rate of evolution considerable and exposes the specie to deletion if they encounter a disease or environmental condition they cannot overcome.