Thanks to their durable structure — from enamel to plaque — teeth have once again shed light on the history of human evolution.
In one study recently published in the Journal of Human Evolution, researchers suggest that uniform pitting on tooth enamel dating back two million years — seen in specimens from Paranthropus, Australopithecus, and Homo, three of the most well-known hominin genera — may reflect a genetic trait rather than signs of disease or malnutrition.
“The uniform pitting appears regularly in both eastern and southern African Paranthropus, and also in the earliest eastern African Australopithecus teeth dating back around three million years,” wrote Ian Towle, a research fellow in biological anthropology at Monash University in Australia, in The Conversation. “But among southern African Australopithecus and our own genus, Homo, the uniform pitting was notably absent.”
Interestingly, similar pitting has also been observed in Homo floresiensis, the so-called “hobbit” species discovered in Indonesia. If confirmed, this could suggest that H. floresiensis may have an evolutionary history more closely tied to earlier Australopithecus species than to modern humans.
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146,000-year-old skull
In a separate study published in Science, researchers used dental plaque from a 146,000-year-old skull — known as the “Dragon Man” — to extract ancient DNA and gain new insights into Denisovans, an elusive group of archaic humans.
The skull, discovered in Harbin, China, contained dental calculus (hardened plaque) that preserved mitochondrial DNA. After extracting it, researchers identified 122 amino acid substitutions characteristic of the Hominidae family, confirming the skull belonged to the genus Homo.
By comparing the mitochondrial DNA with known Denisovan sequences, the scientists determined that the Harbin individual likely represents an early lineage of Denisovans.
As Discover Magazine reported, “The find suggests that Denisovans occupied a wide area of Earth during the late Middle Pleistocene, spanning from Siberia to Northeast China.”
The team also built a reference library of mitochondrial DNA sequences from the Harbin skull — offering a new tool to explore ancient human ancestry.
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