A small dutch poplulation settled in south africa in the 17th centrury and became known as afrikaners. By chance a few dutch settlers carried the gene for huntingtons disease. Today huntingtons disease occurs at a relatively highfrquency in this popluation. This is example of.

Mutation

Explanation:

A mutation can be described or explained a change that occurs in the DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors.

This means that the occurrence of Huntingtons disease in high frequency is because of mutation. This is possible because during the settlement of the dutch in 17 the century in South Africa, they might had intercourse with the people that have the disease and inherited it. And they will be transferring the gene with the trait of the disease from one person to another through sex. And this will result to high number of the disease in their population.

Huntington's disease in South Africa is an example of genetic drift, specifically, it is an example of the founder effect.

Explanation:

The founder effect is a special case of genetic drift, where a few organisms of one population settles down in a new area carrying the genes of the original population.

Genetic drift is the random change in the allelic frequency in a population, from one generation to the other. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time, and eventually, some alleles get lost, while some other might set.  

Founder effect refers to the consequences that occur from the origin of a new population that derives from a small number of founder individuals that come from an ancestral bigger population. This small group shows poor genetic variation and a high possibility of expressing a peculiar allelic composition.  In the exposed example, the principal consequence is the increasing number of individuals with Huntingtons´ disease.

If the number of individuals that originated the new population is very low, the founder effect will be very extreme, because the effects of the genetic drift are inversely proportional to the original number of individuals, which in this example, is the small dutch population settled in South Africa in the 17th century.

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