Neutral alleles, in the Kimura and Ohta sense of neutral, because of their low mutation rates, their slow evolution by random genetic drift, and their benign effect on the structure and function of protein, cannot participate in the reduction of hominid phenotypic traits during the upper Pliocene and the Pleistocene.
Williams, Robert C.
"The Probable Mutation Effect: Neutral Alleles and Structural Reduction,"
2, Article 9.
Available at: https://digitalcommons.wayne.edu/humbiol/vol50/iss2/9