Fig. 1.

Clustering of recessive genes in a consanguineous kinship group. In communities with customary consanguineous marriage, the population make-up consists largely of several or more kinship groups (referred to, for example, as tribes, clans, biraderis). Each kinship group is made up of a large number of extended families. Figure 1 shows the clustered concentration of individuals potentially at-risk for the same recessive disorder in extended families of one such kinship group. Other recessive disorders may also be clustered in this or other extended families within the same kinship group. This is in contrast to the sporadic manifestation of recessive disorders in populations with random partner choice