Class blog for sharing and commenting on current events in biology.

Thursday, December 19, 2013

Toe Fossil Provides Complete Neanderthal Genome


Freddie Reichel
Core Biology Honors
Block D Odd
            Zimmer, Carl. "Toe Fossil Provides Complete Neanderthal Genome." Nytimes.com. N.p., 18 Dec. 2013. Web. 19 Dec. 2013. <http://www.nytimes.com/2013/12/19/science/toe-fossil-provides-complete-neanderthal-genome.html?ref=science>.
            From a single toe bone in a Siberian cave, scientists have sequenced the entire genome of a 130,000–year-old Neanderthal, a feat that surpasses any previous work on Neanderthal genes.  The preciseness of the newly characterized genome is equal quality to what scientists would accomplish if they were sequencing the DNA of a living person.  Now published in Nature, the new Neanderthal genome provides new novel insights and information on ancient human ancestor DNA.  Earlier in December, scientists reconstructed a small segment of genes from a fossil from Spain that was 400,000 years old, setting a record for the oldest human DNA ever discovered.  However, the Spanish DNA only demonstrated vague clues about human evolution whereas the new Neanderthal genome offers more information about previously unanswered questions.  For example, the bones of the Neanderthal were highly inbred, suggesting more interbreeding between ancient human populations than prior knowledge.  The authors of the study offered comparisons between the Neanderthal genome to modern human DNA to clearly see the lineage of the human species and what makes it so unique.  As a result, the authors of the study compiled a list of mutations that have evolved in humans over the course of 600,000 years.  The first fossils of Neanderthals were found in 1856 and scientists have been intrigued about Neanderthals ever since.  An ongoing debate has been whether Neanderthals interbred with humans or if they are completely separate species.  The fossil record of Neanderthals is mostly found in Spain and Central Asia with fossil dating back to between 200,000 years ago to about 30,000 years ago.  The scientists were able to build the genome from another sample of DNA from an 80,000-year-old finger bone from a cave called Denisova and were able to reach the surprising conclusion that the genome belonged to a separate lineage of humans that had not been discovered from the fossil record before.  The scientists named deemed these people the Denisovans.  In a comparison of the Denisovan and Neanderthal genomes to modern human DNA, Dr. Paabo concluded modern men, Neanderthals and Denisovan are all descended from a common ancestor that lived several hundred thousand years ago. The ancestors of modern humans split away to create their own lineage.  The researchers also discovered the DNA of Neanderthal and Denisovan in the genomes of modern day living humans.  It was concluded that modern humans interbred with both Neanderthals and Denisovans, which resulted in the two lineages becoming extinct.
            This is groundbreaking research.  The article helped to summarize the hundreds of thousands of years of human lineage, what we derived from and how our DNA has evolved.  Formally, there was a separate lineage of humans and the interbreeding of a Neanderthal and Denisovan is what lead to the two lineages becoming extinct.  This research helps to better understand where man came from.
            This article was written very clearly and none of the vocabulary was too sophisticated or medically oriented.  The author could have included more background information on the discoveries made prior to the completion of the Neanderthal genome and included more photographs of the fossils.

3 comments:

  1. I enjoyed reading your current event a lot, Freddie! It was very interesting to know that such a small, insignificant part of the body could lead to so much advancement in the history of our ancestors! Aspects that I truly loved about your article was the fact you chose this article, it's really interesting and I'm glad you brought it up, I also enjoyed the terms that weren't all too medically oriented. It was a little difficult for me to understand the words but I liked that. A little effort is never bad! One last thing that I also really liked about your current event was the opening. It was extremely well written and I appreciated how you were able to create a good "hook" and take me into the article in a deeper sense! From reading this I was able to truly understand how these species became extinct, not knowing anything about that topic before. I felt very enlightened by that, and also I was very impressed by the insane amount of science involved in this fossil found. It wasn't just that you could dig it up and say, "Oh, this is how the Neanderthals and Denisovans became extinct," it had to actually involve true scientific and biological testing! Another thing I learned was that the Neanderthals interbred. It makes sense now, knowing but it wasn't something I had thought about before. I was very impressed by the vocabulary you were able to use and make it understandable to a reader such as myself. I don't think the original article had that accessibility to make the reader understand the vocabulary better. One suggestions I had was that I didn't really understand too much how this affects society. It seemed as if you were going to go into it deeper but then didn't go the full way through. That was the only part that was slightly confusing for me as the reader. Other than that, this was an overwhelmingly well done current event! I much rather read your version than the actual article!

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  2. I thought the article you chose was interesting, and you did a good job summarizing it. I liked how you didn’t write too much or give too much information, there was an adequate amount of facts and you emphasized important details. I think it is really amazing how only one toe was used to make so many conclusions about Neanderthals. All I knew about the species was that they were separate from homo sapiens, and weren’t as intelligent. They also moved around a lot, and probably communicated and interacted with other species of the same family, which you talked about in your summary. Now, I know that Neanderthals may even be a subspecies of homo sapiens. You also mentioned that Neanderthals fossil history is mostly found in Spain and Central Asia which can say a lot about their migratory patterns. However, what I found most interesting was the discovery of Denisovans, who were a separate species from the Neanderthals, and that from breeding with humans the Neanderthals and Denisovans became extinct; which was fascinating since scientists were able to track Neanderthal genes in modern day humans. Most of all, I thought your article was extremely relevant to society and science. These discoveries can better understand evolution and the lifestyle of people pre-Neolithic revolution and the discovery of a new species is a big deal. It would have been interesting if the article had talked more about the scientific process of analyzing the Neanderthal’s toe. Over all I thought you did a great job with choosing an interesting article and explaining it.

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  3. Fascinating! You did a really good job of summarizing the information in this article. I feel like I've learned a lot. The way that you explained the article was very easy to understand. I was not confused at all. I never knew that Neanderthals could be a possibly different species from humans. Then again the only evolutionary species I know for mankind are homo erectus, homo sapien, and homo hibilus. It is interesting how scientists developed a DNA sequence from a single bone. I wonder if there is an age at which DNA ceases to be expressed in fossils?
    The only critique that I have for you is that your relevance and critique paragraphs could have been a little longer. Compared to your summary paragraph, which was chock full of information, they were a bit short. I understand that this is a breakthrough, but how will this affect science in the future?

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