A small founding population of a few hundred Europeans in North America had an unusually high frequency of an allele that causes polydactyly six fingers Many generations that followed had cases of?

The Founder Effect

The founder effect is when a few individuals of a species form a new population. The gene pool composition, therefore, is not reflective of the gene pool of the original population. Think of this as a small number of people starting their own colony.

This is an example of the Founder effect because Polydactyly is a dominant trait. And in a large population, it will be rare finding a person with a 6th digit. In a smaller population, however, polydactyly has a higher frequency of this allele, because the smaller the population, the higher the sensitivity for inbreeding and lower genetic variation. So, polydactyly (dominant allele) + Increase inbreeding= Higher polydactyly allele frequency.