Question

Geneticist have determined that the majority of individuals in an isolate island population have blood type b. type a blood is found to be more common in the mainland populations from which the island was settled. how would a geneticist explain the dominance of blood tpe b in the island population.
A- Random mutations have occurred in the island population.
B- Genetic drift has reduced the frequency of type A individuals.
C- Natural selection has only occurred in the mainland population.
D- Environmental conditions on the island are less favorable for type B individuals.

Answer 1

B. Genetic drift has reduced the frequency of type A individuals,which explains the dominance of blood type b in the island population.

Genetic drift is a mechanism of evolution during which allelomorph frequencies of a population modification over generations because of sampling error.  The Genetic drift happens in populations of non-infinite size, however its effects are strongest in tiny populations.

Answer 2

The correct answer is genetic drift has minimized the frequency of type A individuals.

Usually, genetic drift takes place in small populations, where infrequently happening alleles encounter with a greater chance of getting lost. Once it starts, genetic drift will continue until the involved allele is the only allele present in a population at a specific locus or until the allele involved is lost.

In the given case, allele A is lost due to genetic drift phenomenon.