"At the time there were over 5 million orphans in Southern Africa as a result of HIV. Drug development was being driven out of the United States and Europe and therefore tailored to the majority population, including a deletion within the CCR5 gene only carried by people of European ancestry. This genetic target was absent in African ancestral South Africans," said Professor Hayes.
"One of the biggest issues with not including all indigenous people in genomics is that medicines tailored towards genomic profiling only target anomalies that can be found in current databases. If there are no African genomes in the database, then Africans are excluded from drug development."
All modern humans shared a common ancestor roughly 200 thousand years ago in Africa. The closer a population resides to our early beginnings, the more diversity is carried in the DNA of that population.
To date Hayes has identified the most diverse human genomes within the Southern African Bushman (Khoesan) peoples. In contrast, Europeans and Asians show the least genomic diversity, having gone through a major 'bottleneck' (population reduction) when leaving Africa some 35,000 to 25,000 years ago.
"We found more genetic diversity between two click-speaking Bushmen, who live 500 km from each other, than between me (a red haired) and someone from China," explained Hayes.
"By sequencing the complete genomes of !Gubi and the Archbishop we were able to add 1.3 million gene variants to the databases that weren't there previously -- simply because people hadn't looked in Africa."
Hayes believes that Africa holds many secrets to understanding human disease that have not been tapped. For example the significant link to prostate cancer and aggressive prostate cancer disease observed in men of African ancestry. "Although the Archbishop has been diagnosed with prostat
|Contact: Alison Heather|
Garvan Institute of Medical Research