AUSTRALIAN Aborigines have differences in a few immune genes that might explain why they suffer such high rates of certain medical problems.
鈥淭he data are very preliminary but they imply that Australian Aborigines would mount a more vigorous inflammatory response to infection than Europeans,鈥� says Rodney Scott of the University of Newcastle in New South Wales, Australia. His team actually set out to study prehistoric human migration by looking at variations in the genes coding for three immune system proteins in Europeans, Bangladeshis, Australians of European descent and three Aboriginal communities in central Australia.
But they also showed that Aborigines are much more likely to have gene variants thought to increase the expression of the pro-inflammatory immune signalling protein IL-1 and decrease expression of IL-10, which shuts down IL-1 production, Scott told a conference on human origins in Sydney last week. He speculates that these variants were once more common generally, but that natural selection weeded them out in people living in crowded towns, where infections were rife.
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Whether having these genes actually translates into higher levels of IL-1 has yet to be investigated. But Aborigines suffer much higher rates of a number of diseases compared with white Australians. About half of Aboriginal schoolchildren suffer from middle-ear infections as a result of an overactive inflammatory response, for instance. 鈥淥ther populations of low socioeconomic status in Australia don鈥檛 have that over-representation,鈥� says Scott. If genes are partly to blame, it may be possible to reduce infections with the appropriate drugs, Scott says.
But there are certainly other factors that contribute to the generally poorer health of Aborigines, as Sheila van Holst Pellekaan of the University of Sydney points out. Aboriginal mothers are less likely to get antenatal care, for instance, and are more likely to have babies of low birthweight, which is linked to an increased susceptibility to infections later in life.