Researchers working at Boomplaas Cave in South Africa have recovered ancient DNA from a 50,000-year-old tooth fossil belonging to a mountain reedbuck antelope [1]. In sub-Saharan Africa, where organic remains usually degrade rapidly in the hot climate, the discovery is highly significant because it shows that the region’s genetic preservation limits can extend back tens of thousands of years further than previously demonstrated.
The research team led by paleogenomics specialist Deon de Jager of the University of Copenhagen examined more than 300 animal teeth from the last 110,000 years [6]. Genetic data obtained from these remains, which date mainly to the later stages of the Last Glacial Period, are opening a new window onto the evolutionary trajectories of regional species and their patterns of gene flow.
Genetic preservation in Africa’s harsh climate
The hot and humid climate of sub-Saharan Africa causes DNA molecules to break down quickly, which has long imposed serious limitations on ancient genetic research in the region. Until now, the oldest human DNA recovered there came from 18,000-year-old bones found in a rock shelter in Tanzania, while the oldest animal DNA was from a 9,300-year-old antelope in South Africa. The new find pushes this boundary back by almost a factor of five and challenges earlier assumptions.
In addition to the 50,000-year-old antelope DNA, the researchers successfully isolated DNA from extinct long-horned bison dating to 12,000 and 21,000 years ago. Shortly after this work, another antelope genome, around 42,000 years old, was sequenced in Ethiopia, suggesting that DNA in African environments may be far more resilient than previously thought.
Tracing the deep history of humankind
The African continent occupies a central place in research on human origins and migration routes [2]. Major dispersal events that took place around 50,000 years ago and the social networks of Stone Age populations are being reconstructed in increasing detail thanks to ancient DNA studies [3][4]. Even so, specialists note that the chances of recovering DNA from much older human relatives, such as Homo naledi, which disappeared around 240,000 years ago, remain very low because of Africa’s extremely harsh taphonomic conditions.
Nonetheless, deep cave systems with stable temperatures and high-altitude regions with colder climates are thought to hold the potential for preserving far older genetic records in the future.
Sources and further reading
- [1] Scientists show that DNA can last for up to 50000 years in ...
- [2] Ancient DNA helps reveal social changes in Africa 50,000 years ago that shaped the human story
- [3] Ancient DNA Sheds New Light on Africa's Stone Age
- [4] Ancient human DNA from north Africa reveals hidden history of the Sahara | Natural History Museum
- [6] Evaluation of DNA and collagen preservation in Late ...
Image & News Source: Live Science - Archaeology / livescience.com