Scientists have completed a comprehensive study of genetic diversity in Sub-Saharan Africa.

The African Genome Variation Project analysed the DNA of 1,800 people living across the continent.

The data is helping scientists to understand how susceptibility to disease varies across the region and has provided more insight into how populations have moved within Africa.

The research is published in the journal Nature.

Until now, most studies examining genetic risk factors for disease have focused on Europe. Little has been known about Africa, the most genetically diverse region in the world.

Dr Manj Sandhu, from the Wellcome Trust Sanger Institute and the University of Cambridge, said: "We originally set out to look at chronic diseases in Africa, and one strategy to understand the causes of those diseases is to look at the underlying genetic susceptibility.

"But to do that, you need a pretty good grasp of the variation in genomes across the region, but we realised that information wasn't available."

To find out more, a team of African, UK and US researchers collected genetic material from 1,800 people in Sub-Saharan Africa, including 320 whole genome sequences.

The researchers found that there were some key regional differences.

For example, people from South Africa are less likely to carry a genetic mutation that offers protection against malaria than those from other parts Africa.

And globally, Africans are more likely to have a greater risk of high blood pressure than Europeans.

However, the researchers also found that there were more genetic similarities across Africa than they had thought.

Dr Sandhu said: "The diversity among populations is not as diverse as we expected it to be. That's good, because it means we can now design large scale trials to understand diseases susceptibility.

"If we can clearly understand the biological processes and individual susceptibility to a disease for a given individual in a given continent, we can start to understand how we could intervene - either in a therapeutic or development of a medicine approach - to control and manage that disease."

He added that the genetic data could help researchers who are trying to understand why some people in Africa are more susceptible to viruses, such as Ebola, than others.

The African Genome Variation Project has also provided more insight into how ancient populations moved within Africa.

The researchers found that many Africans have some Eurasian DNA within their genetic ancestry, which suggests that Eurasians migrated back into Africa many thousands of years after they first left.

And several of the populations were descended from the Bantu, a group that spread across Africa about 5,000 years ago.