Treasures from the Past: Giving Us Answers at Last

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Treasures from the Past: Giving Us Answers at Last

In 2008, scientists discovered a finger bone (phalanx) of a young female believed to have lived 30-50 thousand years ago, at the Denisova Cave, Siberia. The artifact was found in layer 11 of the excavation site and where other relics have also been dug out. Aside from the finger bone, microblade and body ornaments typical to the Upper Paleolithic era were also dicovered. They also stumbled upon stone tools believed to be in the earlier Middle Palaeolithic age.

Paleolithic Era Timeline

Researchers used DNA extraction to unfold the mystery of the fossil. They have focused on a type of DNA which is mitochondrial DNA (mtDNA). Mitochondria are known as the powerhouses of the cell. They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy-rich molecules for the cell.They also have their own DNA that is separate from the nucleus. Because each cell has thousands of mitochondria, mtDNA is much more plentiful and is more likely to be preserved.

Using this method to the finger found in the cave, they have sequenced the genome of an obsolete hominin to about 1.9 fold coverage. Based on the results of the DNA extraction, the individual can be concluded that is it from a group that shares common origins with Neanderthals. They have labeled the fossil Denisova 3 or X Woman. This discovery is amazing because scientists have unlocked another missing link in the evolution of man.

During an excavation in 1982 at the same cave in Denisova, Russia, archaeologists unearthed a tooth, specifically a molar. The Denisova 2, as they call it, is said to belong to a child thousands of years ago. At that time, the origin of the tooth is a mystery. Nowadays, researchers now have the capability to know the origin of the fossil record.

Using the finger bone to sequence the species’ genome, Svante Paabo and his team were surprised with their findings. The Denisova hominin differed at an average of 385 positions from modern humans and 376 from Neanderthals, Meaning, they have newly discovered another species of hominin. And in addition, they were able to answer the mystery of 1982 - the origin of the fossilized tooth, and how old it maybe. “We think based on the DNA sequences that Denisova 2 is at least 100,000 to 150,000 years old. Or a bit more,” said Viviane Slon, a doctoral candidate at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. As of now, they are not giving the new species a name, until they have fully solved the puzzle. They are now planning to use nuclear DNA from the finger bone. If successful, they might be able to fit another jigsaw piece in the mystery of the past.

Depiction of possible "missing link" in the evolution of man,

On the other side of the map, another discovery has been made on teeth samples by David Frayer, professor emeritus of Anthropology, and University of Kansas researcher. This time, they are from the Denisovans’ cousins - the Neanderthals. He discovered toothpick grooves and signs of manipulations by Neanderthals of 130,000 years ago with their teeth. He then hypothesized that these are pieces of evidence of prehistoric dentistry.

"As a package, this fits together as a dental problem that the Neanderthal was having and was trying to presumably treat itself, with the toothpick grooves, the breaks and also with the scratches on the premolar," claimed Frayer. Researchers took a look at four isolated but associated jaw teeth on the left side of the Neanderthal's mouth. The specimen was found at the Krapina site, Croatia. These teeth were discovered between 1899-1905 and they are said to be 100 years old upon the excavation. Past research in the fossil record has observed toothpick grooves about 2 million years ago. “We did not identify what the Neanderthal would have used to produce the toothpick grooves, but possibly could have been a bone or a stem of grass,” said Frayer.

Frayer and his team used a light microscope to examine the fossils. A light microscope uses visible light and magnifying lenses to examine small objects not visible to the naked eye, or in finer detail than the naked eye allows. In the process, they observed occlusal wear, toothpick groove formation, dentin scratches, and lingual enamel fractures.

These are what researchers found in the fossil.

They have found out that the molars, together with the M3 (wisdom tooth), are pushed away from its normal place. In addition, they found six (6) toothpick groves among those teeth. Thus, having a conclusion that Neanderthals must have been pushing something into their teeth. ”The scratches indicate this individual was pushing something into his or her mouth to get at that twisted premolar," Frayer said. These findings may lead to a conclusion that there was dentistry before but, according to Frayer, there is no specimen that combines all hypotheses together that will presume that they really are treating dental problems.



Kayla Zosa

The "Real" Missing Link in Human Evolution