Answer:
A mutation may be bad and good depending on the particular environmental conditions
Explanation:
For example, the falciform anemia is a hereditary disease caused by a mutation where the ability to transport oxygen of red blood cells is reduced; however, this genetic disorder is widespread in some African populations because it is a condition that confers resistance to falciparum malaria. In consequence, falciform anemia is a detrimental mutation that may also be beneficial in endemic malaria regions.
Moreover, it is important to note that the higher proportion of non-synonymous substitutions are not subject to selection (only a minor percentage are positively selected) because they are generally localized within non-coding regions, thereby having neutral status.
