Denisovan

From Simple English Wikipedia, the free encyclopedia
Jump to navigation Jump to search
The Denisova Cave, where the "X woman" was found
Denisova Cave is located in Russia
Denisova Cave
Denisova Cave
Location of Denisova Cave in the Altai Mountains of Siberia

The Denisovans or Denisova hominins are archaic humans in the genus Homo. They may be an extinct species or subspecies.

Scholars found Denisovan bones for the first time in March 2010 in the Denisova Cave in the Altai Mountains in Siberia. The scholars saw that Neanderthals and modern humans had also lived in the same cave.[1][2][3]

One of the bones in the cave was a piece of finger bone from a Denisovan girl. She lived about 41,000 years ago. Gene scientists studied the DNA in the bone. They found the Denisovan girl had about 3% to 5% of the same DNA as Melanesians and aboriginal Australians and around 6% in Papuans deriving from Denisovans.[4][5][6]

Scientists also looked at mitochondrial DNA (mtDNA) from the finger bone. Mitochondrial DNA is DNA from the mitochondria, which are tiny organs inside human cells. Millions of years ago, the mitochondria lived on their own, so their DNA is more like bacterial DNA than like other DNA in the human body. Because mitochondria don't mate with each other, their DNA changes very slowly. This means scientists can use mitochondrial DNA to see where populations of people have lived and gone and which humans are related to each other. The mitochondrial DNA in the Denisovan girl's finger bone showed her mitochondria were different from Neanderthal mitochondria and modern humans' mitochondria. Scientists also looked at the nuclear genome from this bone. They figured out that Denisovans came from the same ancestors as Neanderthals.[7]

DNA analysis showed that modern humans, Neanderthals, and the Denisovans came from the same ancestors around 1 million years ago.[8]

The mtDNA analysis also seemed to show that this species was the result of a migration out of Africa that came after Homo erectus left Africa but before the ancestors of many modern humans left Africa.[8]

Fossils[change | change source]

So far, the fossils of four distinct Denisovans from Denisova Cave have been identified through their DNA: Denisova 2, Denisova 3, Denisova 4, and Denisova 8. Denisova 2 and Denisova 3 are young females,and Denisova 4 and Denisova 8 are adult males.[9]

Anatomy[change | change source]

So far, only a finger bone, a toe bone and two teeth are the only body parts that have been found.  The finger bone is from a woman.  It is broader than a human finger.  This fact suggests that Denisovans were more robust than any modern humans.

Mitochondrial DNA analysis[change | change source]

The mtDNA from the finger bone differs from that of modern humans by 385 nucleotides in the mtDNA strand out of approximately 16,500. This  is more than the difference between modern humans and Neanderthals, which is around 202 bases.[3]

References[change | change source]

  1. David Leveille (2012). "Scientists map an extinct Denisovan girl's genome". PRI's The World. Retrieved 31 August 2012.
  2. Brown, David (2010), "DNA from bone shows new human forerunner, and raises array of questions", Washington Post
  3. 3.0 3.1 Krause, Johannes; et al. (2010), "The complete mitochondrial DNA genome of an unknown hominin from southern Siberia", Nature, 464 (7290): 894–97, Bibcode:2010Natur.464..894K, doi:10.1038/nature08976, PMID 20336068
  4. "Callaway, Ewen (2011). "First Aboriginal genome sequenced". Nature. doi:10.1038/news.2011.551.
  5. "About 3% to 5% of the DNA of people from Melanesia (islands in the south-west Pacific Ocean), Australia and New Guinea as well as aboriginal people from the Philippines comes from the Denisovans." Oldest human DNA found in Spain – Elizabeth Landau's interview of Svante Paabo
  6. Harmon, Katherine (2012). "Humans interbred with Denisovans". Scientific American. Retrieved 2016-08-24.
  7. Carl Zimmer (22 December 2010). "Denisovans Were Neanderthals' Cousins, DNA Analysis Reveals". NYTimes.com. Retrieved 22 December 2010.name="Callaway.
  8. 8.0 8.1 Katsnelson, Alla 2010. New hominin found via mtDNA. The Scientist (24.03.10)
  9. Slon, Viviane et al 2017. A fourth Denisovan individual. Science Advances 3 (7): e1700186. doi:10.1126/sciadv.1700186. PMC 5501502. PMID 28695206.