{"id":264869,"date":"2025-05-31T06:02:29","date_gmt":"2025-05-31T06:02:29","guid":{"rendered":"https:\/\/peraltafinancing.com\/aerospace\/scientists-investigate-2-2-million-year-old-tooth-enamel-to-unravel-the-mysteries-of-ancient-human-relatives\/"},"modified":"2025-05-31T06:02:29","modified_gmt":"2025-05-31T06:02:29","slug":"scientists-investigate-2-2-million-year-old-tooth-enamel-to-unravel-the-mysteries-of-ancient-human-relatives","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=264869","title":{"rendered":"Scientists Investigate 2.2-Million-Year-Old Tooth Enamel to Unravel the Mysteries of Ancient Human Relatives"},"content":{"rendered":"


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By studying proteins preserved in teeth, researchers determined the sex of four Paranthropus robustus individuals that lived in southern Africa<\/h2>\n
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Sarah Kuta<\/a><\/p>\n

– Daily Correspondent<\/span><\/p>\n

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This skull of a 1.8-million-year-old\u00a0Paranthropus robustus<\/em> individual was unearthed in South Africa, but it was not one of the fossils included in the study.
\n Jos\u00e9 Braga and Didier Descouens via Wikimedia Commons under CC BY-SA 4.0<\/a><\/span>
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Paranthropus robustus<\/em> was a prehistoric, two-legged human relative that lived in southern Africa roughly two million years ago. Scientists have unearthed various P. robustus<\/em> fossils<\/a>, but because of the specimens\u2019 age, they haven\u2019t been able to glean much from them.<\/p>\n

Now, using a novel method, researchers say they\u2019ve determined the sex of four P. robustus<\/em><\/a> individuals by studying their teeth. The new analysis, published Thursday in the journal Science<\/em><\/a>, also reveals insights into the genetic diversity of the broader Paranthropus<\/em> genus.<\/p>\n

For the study, the team analyzed teeth discovered in a cave at the Swartkrans<\/a> paleoanthropological site in South Africa, reports Live Science<\/em><\/a>\u2019s Kristina Killgrove. Because the fossils were so old\u2014dating to between 1.8 million and 2.2 million years ago\u2014researchers could not recover ancient DNA from them. So, instead, they turned to the relatively new field of paleoproteomics<\/a>, or the study of preserved proteins.<\/p>\n

Ancient DNA degrades over time, particularly in hot places like southern Africa. So far, scientists studying hominin remains on the continent have only been able to successfully sequence DNA from material that\u2019s less than 20,000 years old. But proteins can survive much longer than DNA, particularly in hard tooth enamel.<\/p>\n

When they analyzed the fossilized enamel of the P. robustus<\/em> teeth, the researchers were able to identify specific protein sequences found only in males. This allowed them to determine that two of the P. robustus<\/em> individuals were male and two were female.<\/p>\n

They were surprised to learn that one individual, named SK 835, was male. Based on the comparatively small size of that individual\u2019s teeth, researchers had previously thought SK 835 was female, since male hominins tend to be larger than females, on average.<\/p>\n

This marks an important finding, as it supports the idea that dental measurements are not the most reliable way to determine the sex of ancient hominins.<\/p>\n

\u201cPaleoanthropologists have long known that our use of tooth size to estimate sex was fraught with uncertainty, but it was the best we had,\u201d says Paul Constantino<\/a>, a paleoanthropologist at Saint Michael\u2019s College who was not involved with the research, to Science<\/em> <\/em>News<\/em><\/a>\u2019 Bruce Bower. \u201cBeing able to accurately identify the sex of fossils using proteins will be hugely impactful.\u201d<\/p>\n

Further analyses of the fossils\u2019 amino acid sequences revealed that SK 835 was less closely related to the other three individuals than they were to each other. That means it\u2019s possible SK 835 represents a different species altogether\u2014maybe the newly proposed Paranthropus capensis<\/em><\/a>. After all, the team writes in the paper, the recent description of that species shows Paranthropus<\/em> diversity \u201cis currently underestimated and needs to be investigated further.\u201d<\/p>\n

Or, perhaps the small size of SK 835\u2019s teeth can be explained by microevolution\u2014variations between P. robustus<\/em> groups living at different sites. Scientists say they will need to get their hands on more Paranthropus<\/em> fossils from multiple places to know for certain, per Science<\/em> News<\/em>.<\/p>\n

Moving forward, researchers hope they can one day use paleoproteomic methods to map the entire human family tree. Right now, however, their \u201cability to distinguish between different species is limited by the small number of different proteins present in enamel,\u201d three of the study authors tell Live Science<\/em> in an email.<\/p>\n

Scientists are also exploring other protein-sequencing techniques that are less destructive to fossil samples than the current methods. In the meantime, they\u2019re excited about the potential of paleoproteomics to help them learn even more about humans\u2019 ancient ancestors.<\/p>\n

\u201cIt opens entirely new avenues for understanding our evolutionary history [in Africa],\u201d study co-author Marc Dickinson<\/a>, a chemist at the University of York in England, says in a statement<\/a>.<\/p>\n

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