The influence of the founder in population genetics is the loss of genetic advantages that occur when a new generation of the population arises from a very small number of individuals who were previously part of a larger group (for example, a small group of animals survived a mass extinction event). Ernest Meyer was the first to develop the full concept of the term in 1952, and was able to do so using other theoretical work by scientists such as Sioual Wright. As a result of the loss of genetic differentiation, the new generation may be very different from their grandparents both genetically and morphologically. The influence of the founder is believed to lead in some exceptional cases to evolutionary diversity and to the emergence of new types of more sophisticated creatures.
In the picture to the left, indigenous people have almost equal numbers of red and blue individuals, while the three smaller founding groups show that one color can become predominant or fixed (the influence of the founder) as a result of random selection from the indigenous population. A bottleneck may also cause a founding effect even if it does not represent a completely new population.
The influence of the founder is a special case of genetic drift as well as the exposure of the new population to the influence of the founder. They are also often very small populations, and because of this, they appear to be increasingly sensitive to genetic drift, increase in internal reproduction and relatively low genetic differentiation. This can be seen in the limited gene ponds of Iceland, the Isle of the Resurrection and the Pitcairn Islands. Another example of this phenomenon is the enormous proportion of the Deaf population in Martha Vineyard, which led to the development of Marathas Vineyard's sign language.
