Note: Today is the blog's 1 year anniversary. Thank you everyone for your support over the past year. Please continue to enjoy the blog and this newer edition to physical anthropological knowledge.
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.
References:
29 comments:
Awesome blog. I like learning more about the Denisovans!
-Cajen
Out of all of the bones and fragments that are ever found in archaeological sites, do they all contain enough DNA to accurately say what color their hair and eyes were? Considering that the remains are thousands of years old, how does the DNA extraction work with those fossils?
-Cristian Rios
They have been success at extracting DNA from these bones because unlike other older hominid remains, these are not fossils. Fossils are mineralized impressions/casts of the original bones, whereas the Denisovan remains, particularly the tooth, are bone and organic matter that can and still do contain DNA. Paleogenetics has made quite a few strides in technology and scientific methods to allow for the successful extraction of the DNA from these remains, so we can be and are confident at the results that are coming out in regards to the DNA results.
Really weird how they can tell the hair and eye color based off a couple teeth and a finger bone fragment. Technology is incredible.
-Mariah W
DNA is in all parts of our being-be it our hair, saliva, eyes, teeth, bones, etc. As such, we can extract that DNA from any of these objects and be able to understand what an organism was like as DNA is the blueprint of organisms. And technology is incredible because we have only in the last few years been able to get this data, particularly among ancient remains. We were able to get some but not all.
The Denisovans are a really interesting topic because they are a relatively "New" group. I am slightly curious is there any way that the Denisovans could be a link to the missing link?
-Tabatha Pringle
Well, all members of the Homo and Australopithecine (and Paranthropus) genuses are related to the missing link as they are all descendants (per se) of, but as for being a direct link, no. The Denisovans are contemporary with Neanderthals, which makes the Denisovans very young as compared to the "Missing Link" candidates.
So Denisovan are human or a human at a different stage?
They're members of the genus Homo, meaning that they are their own separate species. They are human like based on the fact that they could and did successfully breed with humans, but scholars are not classifying them as humans at this time.
Denisovan is a very intriguing species. A newly discovered branch of our past. It is amazing how just a couple of teeth can have enough DNA to tell you so much information. You would think that after all the thousands of years they have been underground, they would lose that. It will be very interesting to see what they come up with for the looks of the Denisovan other than the hair, eyes, and skin color.
It is very neat learning about all of these new species that are being discovered. Its also fascinating knowing that the human species and Denisovan species mated and had offspring. It makes you wonder what type of discovery will happen next.
Interesting that you bring that up because it was a year ago this month that they discovered a new hominid species in Eastern Europe. It will be discussed briefly in a future chapter (see the lecture notes since the text came out before that discovery).
after reading this blog what part of the population would be consider denisovan species?
Modern populations? None. We have modern populations with more Denisovan DNA than others, but no one modern population is 100% (or anywhere near close) Denisovan. There is a video in the lecture notes that has more information if you are interested in learning more.
This really makes me think about all the other undiscovered species of the genus "Homo" that certain populations may have the DNA of. It really goes to show that we are more diverse of a species in terms of individuals than we originally thought we were. In the next 50 years we may discover another species that a certain population shares 6% of its DNA with.
-Hayden Lloyd
do you think they will every be able to clone them from the dna found like in Jurassic park?
So scientists can extract DNA to determine eye and hair color from a small fragment from physical remains, but can they glean any information regarding facial structure? Have any Denisovan skulls or skull fragments been found? If so, have any reconstructions been done?
Courteney Hedicke, Anth 101
Could we? I don't know. Should we? Probably not. There are several ethical considerations to consider prior to partaking on such research.
Based on my knowledge of genetics (which is rather basic) I would assume we could glean that information, but several of those genes are affected by environmental factors so the information gleaned from the DNA may not give us an accurate depiction of the Denisovans. No other remains have been found at this time from what I understand, and I don't believe we have an accurate reconstruction of the species as of yet.
i like how you can match bone dna to the species. i think its werid but also cool and a very long time to find out who it belongs too. Cant you find who it belongs to with any kind of dna?
Briana banuelos
anthro 102 1001
DNA matching is only as good as the matches available. If you have unknown DNA and no match that unknown DNA remains just that: unknown.
How can one extract DNA from a fragment of bone that small? I'm sure the answer is obvious but I am stumped. Interesting that molar was still so white even after all those years. Tough enamel I guess.
Zachary Forrester
anthro 101 3001 summer
How do forensics teams extract DNA from blood or semen stains? DNA is microscopically small, and the process is painstakingly tedious. Advancements in science have allowed us not only to understand the present but the past, as well.
This was very educational. DNA has become the key to unlocking many mysteries.
Recent research has shown a genetic relationship with modern humans existing in both India and Australia. It will be interesting to fill in the missing pieces of this relationship and establish the full picture of who the denisovians were, where they came form and who they became.
With three years being past so far with this post being put up in 2014 now it being 2017 what further evidence has been research on the topic of Denisovans. This is a very interesting topic.
Paleogeneticists have begun to look into the Denisovan DNA and while all of the results are forthcoming we have discovered that Tibetans and other Asian groups received a gene that enabled them to handle high altitudes.
Jovie Black
Wow, a bone can tell you age, color, hair color etc?
That's amazing, do you think most historic evidence deteriorated?
Do you believe the breakthrough of the Denisovian could lead to even more findings of other new species found within? I know we talked about this in class, but is this the most recent discovery? I could not remember
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