Groundbreaking Research Discovery: Scientists have successfully extracted DNA from a remarkable 50,000-year-old tooth of an African antelope, marking the oldest DNA ever recovered in sub-Saharan Africa, according to a recent study.
This significant finding indicates that DNA can be preserved for tens of thousands of years in sub-Saharan Africa, a region where the hot climate typically breaks down genetic molecules, hindering researchers’ abilities to trace the evolution of several species, including our ancient human ancestors and their relatives.
Contrastingly, some temperate regions, like Spain’s Sima de los Huesos (“The Hole of Bones”), are known for their well-preserved ancient human DNA. This site kept the DNA of a mysterious relative of modern humans, which thrived around 400,000 years ago. In comparison, the oldest discovered human DNA in sub-Saharan Africa is about 18,000 years old, originating from bones uncovered in a rock shelter in Tanzania. Furthermore, the oldest animal DNA recovered south of the Sahara dates back only 9,300 years to a now-extinct antelope found in South Africa.
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In the novel study, researchers aimed to extract DNA from even older specimens. Their analysis of over 300 ancient animal teeth dating back 110,000 years revealed that small quantities of DNA can still be isolated from such ancient remains. This period falls within the Pleistocene, the latter part of the last ice age.
Researchers successfully extracted DNA from a 50,000-year-old reed warbler tooth (Redunka Hrvorfla), a species still inhabiting Africa.
(Image source: Getty Images)
The study, published on May 27 in the journal Quaternary Science Review, describes how researchers extracted DNA from various Holocene bovid specimens, ages less than 11,700 years, and four Late Pleistocene bovid specimens between 12,000 and 50,000 years old. Although DNA was not obtained from many teeth, a few yielded successful results. The oldest DNA extracted originated from the partial molars of the African antelope, known as the reed warbler (Redunka Hrvorfla), found in Boomplas Cave in southern South Africa. Other ancient DNA samples were identified from three extinct longhorn buffalo (Sincerus Antiquus), two of which died approximately 21,000 years ago and one around 12,000 years ago.
Deon de Jager, lead author of the study titled “50,000-Year-Old DNA is Interesting,” and a paleogenomics expert at the University of Copenhagen, expressed his thoughts in an email to Live Science: “While this is an unprecedented finding, I harbour skepticism for a couple of reasons.”
De Jager elaborated that the reed warbler’s DNA is significantly older compared to the subsequent oldest DNA extracted from the long-tailed buffalo, and that traces of human DNA were also identified in the reed warbler sample. These two factors imply that the DNA results for the 50,000-year-old antelope may be incomplete. Nevertheless, the study also revealed the successful sequencing of a 42,000-year-old wildebeest genome from Ethiopia, suggesting that DNA can remain viable far longer in Africa’s climates than scientists previously believed.
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“Indeed, limitations exist for DNA preservation in Africa; however, these boundaries are yet to be clearly defined,” de Jager mentioned. “There are undoubtedly regions in Africa where DNA preservation may be more effective than at the archaeological sites we investigated. Deep caves with stable lower temperatures are great candidates, as well as high-altitude locations with prolonged periods of cold.”
The Late Pleistocene teeth examined by de Jager et al. produced minimal DNA; they have a half-life estimated at about 521 years. Consequently, every 521 years, half of the DNA from the sample diminishes until none remains. Nonetheless, the detected amounts of DNA are still valuable for research, according to De Jager.
This recovered DNA is enough to aid in identifying evolutionary lineages, De Jager pointed out. By accumulating sufficient data, researchers could potentially analyze gene flow and hybridization between species and populations.
These findings further imply that DNA analysis may significantly contribute to our understanding of the evolution of both animals and humans over the last 40,000 to 50,000 years in South Africa. However, it is likely that extracting DNA from our ancient human relatives, such as Homo naledi, which became extinct around 240,000 years ago, or Paranthropus robustus, which vanished roughly one million years ago, remains unattainable.
“I believe there is a chance of successfully extracting DNA from Homo naledi. However, it’s quite limited,” De Jager stated, noting, “One would need to be exceptionally fortunate to have a well-preserved skull still containing bone material, as this would be ideal for ancient DNA extraction. The harsh conditions in Africa render it almost impossible to gather DNA from entities nearly a million years old.”
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Source: www.livescience.com