A mutation that has no selective advantage or disadvantage in comparison with its allele. Theoretically, a neutral mutation may become 'fixed' (i.e. numerically predominant in the population at its locus) after a number of generations, and this would be a form of evolutionary change. There is legitimate controversy over the importance of such random fixations in evolution, but there should be no controversy over their importance in the direct production of adaptation: it is zero.
