Prelims cum Mains

DNA reveals first inter-species child

The News 

  • For the first time, scientists have found the fossil of a child, Denny, born out of different subspecies of human predecessors.

 

Key Highlights

  • DNA analysis of a bone fragment, from a Siberian cave, revealed that the prehistoric female was born out of a Neanderthal mother and a Denisovans father.
  • This is the first time a direct offspring of these two sub-species has been discovered.

 

About Neanderthals and Denisovans

  • Neanderthals and Denisovans are sub-human species or a hominin that existed until 40,000 years ago.
  • While Neanderthals lived in Europe and Asia, the fossils of Denisovans are known only from the cave where the fragment was found.
  • Neanderthals were short, stocky, had large noses (for European winters in the Ice Age), and larger bodies than modern humans.
  • They used fire, tools, sang, tended to the wounded, and drew on cave walls.
  • Our knowledge of Denisovans is too meager as we only have four individual Denisovan fossils.

 

Evolution of Neanderthals, Denisovans and Modern Homo-sapiens

  • Our DNA reveals that modern homo-sapiens are the only hominin lineage to survive. However we are not pure homo-sapiens.
  • The non-African ancestors have interbred with both Neanderthals and Denisovans.
  • The common ancestor of Neanderthals and Denisovans split from the ancestor of modern homo-sapiens over 744,000 years ago.
  • Then, about 300,000 years ago, this subspecies moved out of Africa.
  • One branch went north, into Europe and West Asia, eventually becoming Neanderthals (Green in the Map).
  • The other branch moved east, becoming Denisovans (Red in the Map).
  • Meanwhile, in Africa, 130,000 years ago, modern homo-sapiens emerged.
  • Homo sapiens benefitted greatly from interbreeding with these hominins by acquiring improved resilience and immune systems.

 

Neanderthals (Green in the Map) and Denisovans (Red in the Map)

 

Significance of the study

  • The results offer clues into our own evolutionary history.
  • The study helps us learn about migrations of Neandertals across Eurasia
  • The study could help point out places where Denisovan fossils can be found which are around Melanesia, Micronesia, Polynesia and Australasia.

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