Doma people

The Doma, also Vadoma or Wadoma (singular Mudoma), are a tribe living in the west of Zimbabwe, especially in the Urungwe and Sipolilo districts on the Zambezi river valley. They have few contacts with the Bantu majority.

A substantial majority of this tribe has a condition known as ectrodactyly in which the middle three toes are absent and the two outer ones are turned in, resulting in the tribe being known as the "two toed" or "ostrich footed" tribe. This is an autosomal dominant condition resulting from a single mutation on chromosome number seven. It is reported that those with the condition are not handicapped and well integrated into the tribe. Indeed it may help in tree climbing. The Kalanga of the Kalahari desert also have a number of members with ectrodactyly, and may be related.

The Vadoma are a popular example of the genetic effects of small population size on genetic defects and mutation, in a case of blatant inbreeding depression. Due to the Vadoma tribe's isolation, they have developed and maintained ectrodactyly, and due to the comparatively small gene pool, the condition is much more frequent than elsewhere.

References

• Farrell HB (1984). "The two-toed Wadoma--familial ectrodactyly in Zimbabwe". S. Afr. Med. J. 65 (13): 531–3. PMID 6710256. 
• Ripley's believe it or not (with photo).