A team of researchers has managed to extract DNA from a 50,000-year-old African antelope tooth, setting a new record for the oldest genetic material recovered in sub-Saharan Africa, according to a newly published study.
This discovery suggests that DNA preservation is possible for tens of thousands of years in sub-Saharan Africa, a region where hot climate often rapidly degrades molecules. Previously, this degradation prevented scientists from understanding the evolution of countless species, including ancient human ancestors and relatives, significantly limiting research in the area.
While some temperate regions, such as the Sima de los Huesos in Spain, are known to have preserved ancient human DNA for around 400,000 years, the environment of sub-Saharan Africa has historically proven less conducive to such conservation.
Until then, the oldest human DNA found in sub-Saharan Africa dated back approximately 18,000 years, in bones in Tanzania. The oldest animal DNA was 9,300 years old, extracted from an extinct antelope in South Africa.
In the current study, scientists sought to test the feasibility of extracting DNA from even older skeletons. By analyzing more than 300 teeth from animals that lived in the last 110,000 years, they were able to identify small amounts of DNA even in remains from the Late Pleistocene, the final phase of the last ice age.
The researchers specifically extracted DNA from a 50,000-year-old tooth from an antelope known as the mountain redunca (Redunca fulvorufula), a species that continues to inhabit the African continent today.
Published online May 27 in the journal Quaternary Science Reviews, the study detailed DNA extraction from dozens of Holocene bovids (less than 11,700 years old) and four Late Pleistocene bovids (between 12,000 and 50,000 years old). Although many teeth did not contain DNA, some samples were successful. The oldest DNA came from a partial mountain redunca molar found in Boomplaas Cave in southern South Africa. Other ancient samples included three extinct long-horned buffaloes (Syncerus antiquus), dating back 21,000 and 12,000 years.
Deon de Jager, the study’s first author and paleogenomics expert at the University of Copenhagen, expressed in a statement that “50,000-year-old DNA is exciting,” but also cited initial skepticism for two reasons.
De Jager explained that the reedbuck DNA was significantly older than other samples and that the sample was contaminated with human DNA, although this had been removed. Despite these issues, which made the initial result less conclusive, the team later sequenced the genome of a 42,000-year-old wildebeest from Ethiopia, solidifying the idea that DNA can, in fact, persist for much longer periods in the African climate than previously thought.
