Inbreeding effect on morbidity: III. A review of the world literature.

A review of the international literature on the inbreeding effect on morbidity is presented. For anomalies in general, the estimates of B vary from 0.2 to 5.8, of A from 0.01 to 0.23, and of B/A from 3 to 77. The respective modal estimates are roughly around 0.5, 0.03, and 20. A review of the estimates for specific anomalies also shows a wide range of values; from B = 0.0008, A = 68 X 10(-8), and B/A = 1,176 (for acheiropodia) to B = 2.9, A = 0.24, and B/A = 12 (for "incapacity for military service"). Some estimates of B/A lower than 12 have been obtained for congenital malformations in some countries. An overall analysis of the whole body of data suggests that most of the anomalies are either entirely or predominantly mutational in origin.