Question

the afrikaner population of south africa is descended from a few colonists. today, the afrikaner population has an unusually high frequency of the gene that causes huntington’s disease. huntington’s disease is an autosomal dominant disease and only one allele is needed for the disease (hh, hh). the afrikaners are an example of a founder effect but are also an example of genetic drift. how is the founder effect related to genetic drift?
a in a small population the more advantageous trait becomes more common.
b reduced genetic variation of this small population means that the population may not be able to adapt to new selection pressures.
c the small population size means that the new colony may have reduced genetic variation from the original population and that variation includes the dominant allele for huntington’s disease.
d there are three sources of genetic variation: gene flow, sexual reproduction, and mutation.

Explanation:

The founder effect is a specific type of genetic drift. Genetic drift refers to random changes in allele frequencies in a population, often more impactful in small populations. The founder effect occurs when a small subset of a larger population establishes a new colony, leading to reduced genetic variation compared to the original population. The Afrikaner example shows this: the small founding group had a higher frequency of the Huntington’s disease allele, which became more common in the new population due to the small size (a key driver of genetic drift). Option C directly links the small founder population’s reduced genetic variation (including the disease allele) to the founder effect as a form of genetic drift.

Answer:

C. The small population size means that the new colony may have reduced genetic variation from the original population and that variation includes the dominant allele for Huntington's disease.