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.