Paleogeneticists were able to sequence ancient DNA extracted from a sample discovered in Africa. This DNA was found in the tooth of a mountain redunca that lived in the southern part of the continent about 50 thousand years ago. The results of this study are presented in a scientific publication in the journal Quaternary Science Reviews.
Over the last decade and a half, paleobiologists have made significant progress in analyzing DNA preserved in the remains of ancient animals and humans. This progress was marked by Svante Pääbo being awarded the Nobel Prize in Physiology or Medicine in 2022. Studies demonstrate that under suitable conditions, such as permafrost, DNA can survive for over a million years.
In regions with hot climates, DNA molecules are generally subject to rapid degradation. Because of this, very few ancient genomes from Africa older than ten thousand years have been known until now. Examples include data obtained from North Africa, where the DNA of several people who lived approximately 15–14 thousand years ago was successfully read. Furthermore, in 2024, researchers presented the oldest genome from South Africa, belonging to an individual who died about ten thousand years ago.
A team of scientists from Denmark, Canada, the USA, and South Africa, led by Elin Lorenzen from the University of Copenhagen, conducted a study aimed at examining the preservation of endogenous DNA and collagen in the bones and teeth of wild animals. These samples were extracted from six discovery sites in South Africa. A total of 320 samples were collected, which paleontologists classified as belonging to six species of ungulates inhabiting the late Pleistocene and Holocene. The oldest of these samples was approximately 110 thousand years old.
Researchers tested the DNA preservation in 144 samples and found that it was sufficient to determine the animal's species status in 65 cases. In 62 of these 65 cases, paleogeneticists confirmed the classification of species or genera made by paleontologists. However, in two cases, bones initially attributed to reduncas (Redunca sp.) turned out to be the remains of antelope (Pelea capreolus). A tooth from the Bumplaas cave was also studied: paleontologists assumed it belonged to a large redunca (R. arundinum), but paleogeneticists identified it as the remains of a mountain redunca (R. fulvorufula).
The last sample is particularly significant because, according to the scientists, its minimum age is 50 thousand years, making it the oldest African genome to date. In addition, the team successfully sequenced DNA from three other finds dating back to the late Pleistocene. These finds consisted of teeth from extinct buffalo Syncerus antiquus, found in Nelson Bay Cave. The age of two of these teeth was estimated at 21–23.5 thousand years, and the third at 12–14.1 thousand years. The remaining 61 samples with preserved DNA belong to the Holocene epoch, meaning their age does not exceed 11.7 thousand years (the average age was 3.1 thousand years).
Recent investigations have shown that in rare cases, Pleistocene period finds may contain not only DNA but also RNA. The oldest RNA was sequenced from the mummified tissues of the mammoth steppe yak Yuki, which died in the territory of modern Yakutia about 40 thousand years ago. Separate attention should be paid to data from Taiwan: paleontologists, after studying a fossilized vertebra aged 400–800 thousand years, concluded that large pythons, reaching almost four meters in length, inhabited Taiwan during the Middle Pleistocene. Pythons are currently not found on the island, and the largest modern local snakes rarely exceed three meters.
Researchers managed to identify DNA fragments dating back approximately 50,000 years in an antelope tooth located in southern Africa. This finding significantly contributes to expanding the understanding of the capacity for genetic material preservation in hot climates.
The study involved analyzing over 300 teeth from animals that lived in the last 110,000 years. The results suggest that genetic traces can remain preserved in sub-Saharan Africa for a much longer period than previously estimated.
The investigation, published in the journal Quaternary Science Reviews, focused on bovine fossils and located the oldest material in a specimen of mountain reedbuck, a species of antelope that still exists on the African continent.
The researchers evaluated bone remains of animals that inhabited the area at different past epochs, covering both the Holocene and Upper Pleistocene. Although many of the examined teeth did not have recoverable genetic material, some managed to retain small amounts of DNA.
The oldest fragment was obtained from a partial molar of an antelope of the species Redunca fulvorufula, found in Boomplaas Cave, in southern Africa. Additionally, DNA was identified in the remains of extinct long-horned buffalo, with estimated ages between 12,000 and 21,000 years.
This preservation was notable, given that tropical and subtropical environments generally promote DNA degradation over time. Previously, it was expected that the African climate would hinder the recovery of very ancient genetic material, especially when compared to cold or stable locations.
Despite the importance of the 50,000-year record, the scientists themselves warned that the result must be interpreted with caution. The antelope's genetic material showed a notable difference compared to other records found, and the fossil also presented signs of contamination by human DNA, which was removed during the analysis process.
According to Deon de Jager, a paleogenomics specialist at the University of Copenhagen and the study's first author, the discovery is relevant, but doubts remain about the exact limits of genetic preservation on the African continent. He emphasized that certain scenarios, such as deep caves with constant temperature and high-altitude areas, can create more favorable conditions for maintaining ancient DNA.
Even in small quantities, the recovered DNA provides substantiation for scientists to investigate the evolutionary relationships between various species and populations. Researchers believe that future studies may provide data on lineages, gene flow, and possible interbreeding between animal groups.
The study also opens avenues for a better understanding of the evolutionary trajectory of African animals and, to some extent, human ancestors. However, recovering DNA from very ancient human species is still considered unlikely. Particularly difficult cases include Homo naledi, which disappeared about 240,000 years ago, and Paranthropus robustus, which lived approximately 1 million years ago. According to the researchers, African environmental conditions make locating preserved genetic material from these distant periods extremely complex.
Therefore, the discovery does not negate the challenges of paleogenetics on the continent, but signals that the time span available for studying African history may be more extensive than previously thought.
