One of the original Amish colonies rose from a ship of colonists that came from Europe. The shipâ€™s captain, who had polydactyly, a rare dominant trait, was one of the original colonists. Today, we see a much higher frequency of polydactyly in the Amish population. This is an example of:
natural selection
genetic drift
founder effect
b and c

Now, there is another thing to keep in mind, and that is that the Amish are very strict about their custom, for example, the idea of family and identity. This led them to form couples, only among the members who belonged to the community.

As generations go by, genealogical relationships between individuals in the population become closer. This causes some genes, by mere probability, to become fixed (i.e. they are the only ones left in the population). As a consequence of this, the frequency of rare genes increases (polydactyly). This evolutionary process is known as gene drift.

Histrionicus Histrionicus · Answer 2 · 2021-11-17T07:44:58+01:00

In this given case of Amish colonies polydactyly frequency is higher and this is an example of - d. b and c ( b. genetic drift and c. founder effect.)

Genetic drift is an unpredictable change in the frequency of an allele within a population over time.

Founder effect is a form of genetic drift.

The reduction in genetic variation that form by a small population or few members of a original population is used to establish a new colony known as founder effect.
If this new population is isolated and interbreeds, then the descendent could have a high frequency of trait such as polydactyly in this case.

A founder effect takes place in case of a new colony is begin with a few members of the original population.

Thus, in this given case of Amish colonies polydactyly frequency is higher and this is an example of - d. b and c

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