Scientists have sequenced the genome of a man who lived about 2,330 years ago in southern Africa, and revealed some interesting information about humanity’s ancestry. The man’s genome was found to be one of the earliest diverged, which means that his DNA is akin to the earliest humans who lived in the region, about 200,000 years ago. The skeleton was discovered by University of Cape Town professor Andrew Smith back in 2010. It was located in an area close to a site where human footprints as old as 117,000 years were found.
The skeleton was first examined by University of Cape Town’s Professor Alan Morris, a biological anthropologist. He showed that the man spent his time diving into water for food, because there was a growth in the specimen’s ear canal called “surfer’s ear”. By performing tests on seashells found near his grave, it was determined that he did indeed have a diet rich in seafood. He was in his fifties when he died, according to his teeth condition and osteoarthritis.
After this initial analysis, an expert in African genomes, professor Vanessa Hayes from the J. Craig Venter Institute in San Diego, California, was contacted to do further studies on the specimen. The skeleton’s DNA was sequenced from mitochondrial DNA, which is the DNA inherited from the maternal side. It was the study of Mitochondrial DNA that proved the human race descended from Africa, and it is widely used to derive common ancestry. Mitochondrial DNA is also used to provide clues on evolution and modern human prehistory.
Paleogeneticist, Professor Svante Paabo, from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, was put in charge of acquiring and testing the DNA from the skeleton. The process was complicated because the skeleton had been buried in extremely acidic soil (acidic environments can hinder the process of acquiring DNA). By using DNA extracted from the skeleton’s rib and tooth, they generated a complete mitochondrial genome, and showed that the man was from a lineage that has been long thought of as extinct; a line closely related to the human race’s common ancestor.
Hayes states in the study that the man lived in southern Africa, before a mass migration into the area of shepherds from the coast of Angola. His lineage was very different to those early migrants, containing a DNA variant that has never been seen before.
Hayes laments that there is not enough objective genetic sequencing of ancient humans from Africa, as partial genomes from the continent are often compared to those obtained in Europe, which poorly represents the diverse populations of the Earth. She goes on to say that more studies like this one need to be done, to truly understand the roots of human civilization and reduce the “noise” caused by mixing samples, especially with Eurasians, who have less than 5% of Neanderthal DNA.
This study was published in the journal Genome Biology and Evolution, and shows the importance of studying southern African archaeological remains.