 To be clear, however, both selection and drift play an essential role in the neutral theory; on Kimura’s view, selection will quickly eliminate the large number of deleterious mutants and fix the small number of advantageous ones, leaving the remaining mutant alleles as neutral, whereupon they undergo a process of drift (Dietrich 2006). Drift would eventually cause the neutral (and nearly neutral) mutants to either go to fixation or be lost (although they would be polymorphic in the meantime), so that observed molecular differences would be