A well-known community from Africa has so much genetic diversity that two people from different tribes in the community have more differences between them than, for example, an Asian and a European. They are the San Bushmen tribe from South Africa.
A very diverse tribe
It was in a 2010 study that the high variance in genes within the San Bushmen community was first identified. The researchers decided to sequence the whole genome of Bishop Desmond Tutu, the famous anti-apartheid activist from South Africa. His ancestry covers two of the biggest Bantu groups in South Africa, Nguni and Tswama, thereby making him an ideal candidate from the region.
“This work is very expensive so we wanted to maximise the amount of diversity we could get in one individual… He’s a voice for southern Africans and for his people. He’s a chairman of the Global Elders. He provides a genome with a lot of medical history behind it, having survived prostate cancer, polio, and TB, diseases that affect many southern Africans,” Vanessa Hayes, who worked on the study, said to National Geographic. Plus, the Bishop himself is said to have been very willing to participate in the project.
The researchers discovered that the San Bushmen had more genetic differences between their individual members of various tribes than any other population. In fact, the 100,000 member-strong San Bushmen tribe were genetically more diverse than the entire 1 billion Han Chinese population. While a regular San Bushmen has over 4 million genetic variants, a Han Chinese only has about 3 million variants. So, how did this happen? To understand this, one needs to remember that only a small population from Africa went out and populated the rest of the Earth.
“The number of genetic variants that Africans carry did not decrease due to an ‘Out of Africa’ bottleneck, and of all the people of Africa, the San Bushmen seem to have occupied a wide zone of southern Africa in their current state from an immemorial time. This stability has left an imprint on their genome, which is more genetically diverse than any other human group,” according to Insitome.
A study by scientists from the Baylor College of Medicine discovered a wide breadth of genetic variation throughout the African continent. When comparing exome sequencing data from 164 children in Botswana with 150 children from Uganda, the team found that about 13 percent to 25 percent of variations seen in the population from Botswana has not been recorded in public databases previously.
“Our study, one of the first data-driven, population-based genomic studies among African populations, found significant diversity in the genetic makeup of a population from the southern region of the African continent… This study demonstrates the need to get a better handle on the genomic makeup of the continent and its individual countries, because this population is just the tip of the iceberg,” Dr. Neil Hanchard, assistant professor of molecular and human genetics at Baylor, said in a statement (Baylor College of Medicine).
The study not only showed the genetic complexity of Africa, but also suggested that one cannot solely rely on small genetic samples of the African population to reveal important information about the entire African people. The study is expected to be an invaluable resource in understanding the genetic basis of human disease.