Box 1.

Definitions

Genetically isolated population or founder population: a population that is or was geographically, culturally, or for religious reasons isolated and as a consequence has restricted genetic variation. Bottleneck effect: occurs when there is a sharp reduction in the size of a population due to a natural disaster or similar event with, as a consequence, reduction of the genetic variation in the population. Founder effect: the reduction of genetic variation that occurs when a new population is founded by a small number of individuals (founders) from a larger population and this population remains isolated to other populations. Founder mutation: a gene mutation on an identical haplotype background, observed with high frequency in a genetically isolated population in which one or more of the ancestors were carriers of the gene mutation. Recurrent mutation: a gene mutation on more than one haplotype background, reoccurring multiple times in a population history.