A single alpha-globin gene deletion in Australian aborigines.

alpha- and beta-thalassaemias and other haemoglobinopathies have not so far been reported in Australian Aborigines. Using a DNA mapping technique, we tested groups of Aborigines for a deletion form of alpha-thalassaemia and found that there was a single alpha-globin gene deletion (-alpha/alpha alpha) in some populations. The alpha-globin gene deletion was detected in Aboriginal DNA samples collected from Kalumburu in the Kimberley region of Western Australia. It was found also in one sample from Mowanjum, near Derby in Western Australia, and in one from Mornington Island in the Gulf of Carpentaria. It was not observed in Aboriginal DNA samples from the central desert. Further analysis of the alpha-globin gene deletion revealed that it was of the 3.7 kilobase (Kb) (-alpha 3.7) type. However, the -alpha 3.7 deletion in the Aborigines is apparently different from that found in southern Papua New Guinea as it is linked to a different zeta-globin gene polymorphism. The presence of this silent alpha-thalassaemia in several populations of Aborigines may be explained in several ways. The most likely is through contact with Macassans or other voyagers from the Indonesian and Southeast Asian areas.