FOR YEARS, EAST AFRICA has prided itself on being the cradle of mankind. That claim to fame has recently received a big jolt.

A 10-year-old study on African genetics has confirmed that while the continent was home to the earliest humans, the most probable area of origin was in Southern Africa.

Other findings of the study, which involved surveying 121 African populations, four African-American populations and 60 non-African populations for patterns of genetic markers, included the confirmation that Africans are the most genetically diverse people in the world.

The study also established that Africans belong to about 14 distinct ancestral population clusters, each with similar ethnic and linguistic properties.
The findings were published in the April 30 issue of Science Express.

East Africa’s claim to be the cradle of mankind was largely based on a series of stunning archaeological finds around the Great Rift Valley.

The finds were at Olduvai Gorge in Tanzania and northern Kenya. Experts like Louis Leakey said these implied that the region was home to the first human beings.

Among the archaeological discoveries that have lent credence to the Out of East Africa theories are fossils of the first “homo” species.

These were found at Koobi Fora, where Bernard Ngeneo made a major find in 1972, and Lake Turkana, where Meave Leakey more recently discovered the 3.5 million-year-old Kenyanthropus — the “flat-faced man of Kenya”.

The latest genetic study suggests there’s more to it than the fossil record.

East Africa, the study implies, could actually have been a transit point of the first humans as they moved from the area around the South Africa-Namibia border to the Red Sea region, from where they dispersed to the rest of the world.

The genetics study, the first of its kind on the continent, involved 25 teams of African, American and European researchers led by Sarah Tishkoff, a geneticist at the School of Medicine, University of Pennsylvania.

Among the East African researchers in the study were Sabah A. Omar of the Kenya Medical Research Institute (Kemri), and Godfrey Lema and Thomas B. Nyambo of the Department of Biochemistry at Muhimbili University of Health and Allied Sciences in Tanzania.

THE STUDY WAS FUNDED BY, among others, the US National Cancer Institute, the National Institutes of Health, the Advanced Computing Centre for Research and Education at Vanderbilt University and, ironically, the L.S.B Leakey and Wenner Gren Foundation.

In the view of those involved, the new data provides a wealth of new information that can help researchers as diverse as anthropologists and epidemiologists trace population patterns, disease vulnerabilities and the varied effectiveness of medicines in different communities.

“This is the largest study to date of African genetic diversity in the nuclear genome,” said lead researcher Sarah Tishkoff in a statement.

“Our goal has been to do research that will benefit Africans, both by learning more about their population history and by setting the stage for future genetic studies, including studies of genetic and environmental risk factors for disease and drug response.”

Ms Tishkoff and her colleagues say data collected from the genetics study will, for example, enable social scientists to test theories of human migration, cultural evolution and population history in Africa.

For public health officials and other medical experts, the data could act as the linchpin for other studies in new-frontier areas such as disease genes, as well as on the genetic differences that make some individuals more susceptible to conditions like HIV, cancer and malaria.

“We observe high levels of mixed ancestry in most populations, reflecting historic migration events across the continent,” the scientists say in their paper.

“This study helps tease apart the complex evolutionary history of Africans and African Americans, aiding both anthropological and genetic epidemiologic studies.”

The data could help in developing vaccines and more effective medicines for specific populations.

RECENT RESEARCH IN KENYA and Uganda involving commercial sex workers, for example, has shown that despite the widespread prevalence of HIV, a significant number of individuals are immune to the infection.

The women have remained uninfected despite having unprotected sex with as many as 20 clients per day.

Prevalence among the population in the two countries, in contrast, stands at about 7 per cent of the adult population.

A team of Aids experts from the Universities of Nairobi, Oxford and Manitoba have for the past decade been trying to develop a vaccine modelled on the resistant women’s immune systems.