Just How “Human” Are We? At Most, 7% Of Your DNA Is Uniquely Human, Study Finds

A landmark study found that only 1.5% to 7% of the human genome contains uniquely (modern) human DNA. The rest is shared with relatives such as Neanderthals and Denisovans.

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However, the DNA that is unique to us is pretty important, as it’s related to brain development and function.

Researchers used DNA from fossils of our close relatives (Neanderthals and Denisovans) dating from around 40,000-50,000 years ago and compared them with the genome of 279 modern people from around the world. They used a new computational method that allowed them to disentangle the similarities and differences between different DNA with greater detail.

Many people around the world (all non-African populations) still contain genes from Neanderthals, a testament to past interbreeding between the two species. But the importance of this interbreeding may have been understated. The new study found that just 1.5% of humans’ genome is both unique and shared among all people living now, and up to 7% of the human genome is more closely related to that of humans than to that of Neanderthals or Denisovans.

This doesn’t mean that we’re 93% Neanderthal. In fact, just 20% of Neanderthal DNA survives in modern humans, and non-African humans contain just around 1.5-2% Neanderthal DNA. But if you look at different people, they have bits of Neanderthal DNA in different places. So if you add all the parts where someone has Neanderthal DNA, that ends up covering most of the human genome, although it’s not the same for everyone. This 1.5% to 7% uniquely human DNA refers to human-specific tweaks to DNA that are not present in any other species and are strictly unique to Homo sapiens.

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