The disproportionately high appearance of polydactylism among the Amish suggests that _______.

A trait can become unusually common in a small, relatively isolated population if it was more frequent among the population’s founders. The Amish have a higher rate of polydactylism, suggesting the trait was overrepresented in the gene pool of the original Amish settlers. This is an example of the founder effect, not evidence that it is common throughout Pennsylvania.

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