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The field of paleoanthropology is a dynamic one. Paleoanthropologists focus their attentions on ancient human species and human evolution. This is a difficult field due to the lack of concrete information available to scholars, which is in part why scholars are working diligently to uncover new evidence and to decipher it in relation to the currently known information. New discoveries are continually being made, such as the discovery of the Denisovans, which has turned the discipline on its ear.
The field of paleoanthropology is a dynamic one. Paleoanthropologists focus their attentions on ancient human species and human evolution. This is a difficult field due to the lack of concrete information available to scholars, which is in part why scholars are working diligently to uncover new evidence and to decipher it in relation to the currently known information. New discoveries are continually being made, such as the discovery of the Denisovans, which has turned the discipline on its ear.
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| Figure 1: Denisovan finger fragment. |
The Denisovans are a new species of the genus Homo discovered in 2008 in the Denisova
Cave in Siberia, Russia. This was an
accidental discovery by Russian archaeologist Alexander Tsybankov who was
excavating in 30,000 to 50,000 year old deposits. He discovered the remnants of a finger bone
(a distal phalange, end of a finger bone, to be exact, Figure 1). He sent pieces of the bone to two researcher
institutions for identification of the bone as well as further analyses, but it
was the scholars at the Max Planck Institute who discovered that this finger
bone did not belong to any known species-past or present. They were able to recover mitochondrial DNA
(mtDNA) and compared it to modern human and Neanderthal mtDNA in order to
determine the association of the bone fragment, but the bone’s mtDNA matched
neither species. The scholars quickly
realized that they had a newly discovered species on their, or rather its,
hand.
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| Figure 2: Denisovan molar |
This discovery was further confirmed with the unearthing of
two teeth that were later associated with this new species based on the teeth
having the same mtDNA (Figure 2). These
teeth had been discovered prior to the finger fragment, but due to their large
size, they were initially associated with belonging to an ancient bear species. Taken together, these pieces of evidence confirmed
the initial conclusion reached by the mtDNA evidence of the finger
fragment. The Denisova Cave had, at one
point, been the home to a new, different species of the genus Homo that had not been discovered until
that point. The new species has been
dubbed Denisovan, after the location of their unearthing.
But the breakthroughs did not end there. Scholars at the Max Planck Institute managed
to map the entire genome of Denisovan specimen, and they reached several interesting
conclusions. First, the finger fragment
belonged to a young female child who was brown haired and eyed. Second, Denisovans differed from other species
in the genus Homo based on eight
chromosomal differences, which allowed for significant skin and neurological
differences that would account for potential morphological and physiological
differences in the Denisovan species. Third,
the Denisovan DNA was very closely related to that of Homo neanderthalensis (Neanderthals) but also modern Homo sapiens, which suggested that
Denisovans had sexual relations with both Neanderthals and humans. Further analyses clarified that it was human
females who selected for male Denisovans, hence how Denisovan genes ended up
(and remain) in the modern human genome.
This conclusion was probably one of the most earth shattering of them
all given the long held debate about whether or not humans and Neanderthals had
sexual relations that produced offspring.
Further studies into Denisovans are ongoing, particularly
excavations to discover more skeletal materials associated with the
species. While we have an idea of what
the Denisovan DNA is, scholars have not yet determined the morphological
appearance of the species, other than potential hair, eye, and skin
colorings. Future studies should not
only assist in furthering the current understanding of the Denisovans but also
the human lineage itself. It will be
interesting to see what else exists in the family tree of the genus Homo as further study continues.
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