The Founder Effect: Understanding the Impact of Limited Genetic Variation on Populations and its Practical Implications in Medicine

founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

The founder effect is a term used in population genetics that refers to the genetic variation that occurs when a small group of individuals separate from a larger population to establish a new population in a new area. The founders of the new population have a limited genetic pool, which can result in the new population having a genetic makeup that is different from the original population.

The founder effect can have a significant impact on the genetic diversity of the new population. Because the new population’s genetic makeup is derived from a small group of individuals, the genetic variation in the new population will be limited, and some alleles may be overrepresented in the new population while others may be absent. Over time, this can lead to the new population having a different genetic makeup than the original population from which it was derived.

One example of the founder effect can be seen on the Galapagos Islands. The animals that populate the islands, such as finches, tortoises, and iguanas, are believed to have been the result of a small group of individuals separating from the larger mainland population and establishing a new population on the islands. Because the new population was derived from a small group of individuals, the genetic makeup of each species on the Galapagos Islands has evolved differently than their mainland counterparts.

The founder effect can also have practical implications in medicine. In some populations, certain genetic disorders may be more common due to the founder effect. As an example, the Old Order Amish population in Lancaster County, Pennsylvania, has a high incidence of Ellis-van Creveld syndrome, which is a rare genetic disorder. This is thought to be due to the founder effect – the Amish population is descended from a small group of individuals who immigrated to the area in the 1700s, and one or more of those individuals was a carrier of the gene that causes Ellis-van Creveld syndrome.

More Answers: