The traits associated with the recessive allele will not be expressed. Evolution of an organism can occur when the sequence or type of nucleic acids are not correctly duplicated. Frequently natural selection removes mutant individuals from the population if their genes express characteristics that confer a lack of fitness. Occasionally, a mutation can lead to an individual that is more fit in a specific environment than other members of the population. Because this individual is favored by natural selection, the new mutant gene sequences proliferate through the breeding population.
Mutations can also lead to speciation .