On May 1, 2019 a startling new discovery was announced. This announcement had been over 30 years in
the making, and the wait was well worth it because this new information expands
our current knowledge of hominids and human evolution. Today’s blog post will discuss the
implications of the discovery of a mandible fragment found in the Himalayan
Mountains.
In 1980 a Tibetan monk discovered the fragment of a mandible
(lower jaw bone) in the Baishiya Karst Cave in Xiahe, China. This piece was eventually donated to the Lanzhou
University, where it came into the possession of scholars Fahu Chen and Dongju
Zhang. They began studying the piece,
and eventually they teamed up with researchers Svante Pääbo and Jean-Jacques
Hublin of the Max Planck Institute.
Together and with respective teams of colleagues in China and Germany
this group launched a study on the mandibular fragment.
When initial DNA analyses failed (due to a lack of usable
DNA in the specimen) they turned to protein analysis to determine the species
to which this piece belonged. They were
successful with this analysis, isolating several proteins that they used to
determine the origin species. This led
to the discovery that this mandible belonged to a member of the Denisovan
species, which had only been previously identified through DNA of a lone
finger bone. They also were able to
determine, through dental aging methods, that this individual was most likely an
adolescent at their time of death.
These pieces of information are remarkable in and of
themselves, but there was even more gleaned from this information. The initial place of discovery, the Baishiya
Karst Cave high in the Himalayan Mountains, meant that Denisovans were well adapted
to high altitude living, which had until recently been associated solely with
archaic Homo sapiens. The
presence of the Denisovan fossil at this location, as well as the discovery of
a specific gene that allows for such adaptations (the EPAS1 allele) in
Denisovan fossils, means that our hominid ancestors were far more advanced that
previously thought.
This was not the only surprising discovery, however. Previous work had demonstrated that modern Tibetans
and various other human groups carry with them DNA
from Neanderthal, Denisovan, and four yet to be identified hominid species. This means that our hominid ancestors were
not isolated species, as previously thought, but instead were different breeds
of the same species or closely related species that were not only able to but
were regularly interbreeding. This
process led to the passing on of many beneficial genes that continue to exist
among modern humans today.
Together, all of this information is creating quite the stir
in the paleoanthropological and human evolution communities. Once previously believed ideas and paradigms
are shifting or being abandoned in the face of new evidence, and this
additional knowledge is demonstrating how complex evolutionary relationships are. It also demonstrates how advanced our hominid
ancestors were, making way for new ideas and realizations about what it means
to be human.
Bibliography
Chen, F., Welker, F., Shen, C.-C., Bailey, S. E.,
Bergmann, I., Davis, S., . . . Hublin, J.-J. (2019). A late Middle
Pleistocene Denisovan mandible from the Tibetan Plateau. Nature,
409–412.
Koumoundouros, T. (2019, May 1). Jawbone of a
Mysterious Denisovan Has Been Discovered in a Remote Cave in Tibet.
Retrieved from Science Alert:
https://www.sciencealert.com/archeologists-discover-why-the-mysterious-denisovans-had-high-altitude-adaptations
Max Planck
Institute for Evolutionary Anthropology. (2019, May 1). First hominins on the
Tibetan Plateau were Denisovans:
Denisovan mandible likely represents the earliest hominin fossil on the
Tibetan Plateau. ScienceDaily.
Retrieved July 30, 2019 from www.sciencedaily.com/releases/2019/05/190501131405.htm
8 comments:
Team Work
As humans coming together to successful find the DNA of a interbreeding animal was a awesome project. Even though there were not evidence for the first analysis they came together to use a different source. I never knew protein could help you identify an species identity which made this article interesting. To know some of the DNA is to be made by different ideas is iconic.
Crystal Riley
I found this so interesting I have so many questions but don't know where to start. After finding out that our hominid ancestors were not isolated species but had different breeds was it like having different races?
Maya Collier
It is amazing to think that our human ancestors would intermingle with closely related species rather than just species of its exact breed. I think that it is fascinating that with a protein analysis and using dental records that they were able to not only determine the species that the mandible belonged to but also the age. It is amazing that in todays time individuals share DNA with other hominoid species. This is a really interesting topic, and hopefully the discovery of the other four mysterious hominoid species surfaces soon.
-Collin Ankton
Maya, that is an interesting question. As you are just now beginning Introduction to Anthropology you probably are not aware that as anthropologists we recognize that the concept of race is a socioculturally constructed one, and as anthropologists we recognize only one race: the human race. So the analogy is not exactly correct or applicable.
As you will learn in class we have a variety of hominid ancestors that we believed were previous species (and they still may very well have been). They are all different by specific morphological (physical) traits, which is how we track our human evolution. When it comes to certain species, such as anatomically modern humans (us), Neanderthals, and Denisovans it may not have been a matter of different species but different variations within the same species, similar to how there are different types of dogs (e.g. a beagle versus a great dane) but they are still all part of the same species. Therefore we might be renaming Neanderthals to Homo sapiens neanderthalensis and doing similar name changes for Denisovans.
I always am super fascinated with how archaeologist are able to find out someones exact origin just from taking samples from their remains that can be 100s of years old. I like the efforts that are being made to keep their language and culture alive, I wish that it was more common in America to learn other languages and others culture there is a lot of value in language and culture. Interesting article I learned something new!
-Rayven Stokes
I think its cool how archaeologists can determine a species in multiple ways.For example, "When initial DNA analyses failed (due to a lack of usable DNA in the specimen) they turned to protein analysis to determine the species to which this piece belonged." At least they have different tools to back them up. Things like this lead to more great discoveries.
-Jasmine Busby
Very intriguing. Knowing that hominid species weren’t isolated makes me wonder about alot of things. Archaeologists are so smart and to be one you have to have a mind that wants to work and focus. -castrele hoy
The best part of science is that its ever changing with every new discovery, you're never 100% correct. Reading back on this blog post from 2019, in 2021 is a similar checkpoint that scientist had to go through when they found a denisovan in the Himalayan mountains. At that time they only had a finger bone but could still link the mandible to it, I love science.
-Kennedy Thompson
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