Question

Scientists observing a species of fish notice that some individuals exhibit a lack of dark pigment, a condition known as oligomelanism. A survey of the population years later does not find any oligomelanic fish. This loss of genetic information within the population is an example of .

Answer 1

Genetic drift — a random change in allele frequencies that can lead to loss of alleles (and thus traits like oligomelanism), especially in small populations.