11. Hence, almost near neutral mutations result in phenotypes that are weakly selected [ 1 ]. 12. Mutations which may have developed allelic variations which code for lactase production into adulthood are simply neutral mutations . 13. Kimura developed mathematical models of the behavior of neutral mutations subject to random genetic drift in biological populations. 14. Neutral mutation has become a part of the neutral theory of molecular evolution, proposed in the 1960s.15. By this reasoning, the accumulation of these neutral mutations should only be influenced by the mutation rate. 16. These non-neutral mutations are thought to have special significance evolutionarily when they affect gene regulatory elements. 17. This theory suggests that neutral mutations are responsible for a large portion of DNA sequence changes in a species. 18. Many of the mtDNA have far more mutations and at rarely mutated coding sites relative to expectations of neutral mutations . 19. Therefore, the neutral mutation rate in individual organisms should match the molecular evolution rate in species over evolutionary time. 20. Hiroshi Akashi more recently proposed a bimodal model for the DFE, with modes centered around highly deleterious and neutral mutations .
