Genetic evolution of the Samaritans.

Detailed pedigrees of the small Samaritan isolate covering the last thirteen generations and consisting of 82 founders and 670 descendants allowed calculations of (a) the probability of origin of genes from particular founder members, and (b) the total number of descendants from each founder. Analysis of the matrix of distances between the thirteen generations identified the kind and the direction of the evolution of this community: rapid evolution from the first to the eighth generation due to the small population size, slowly progressing towards a stable state in the last three generations.