Every year we discover some new species which are extinct or they live in secluded areas. Such are these modern Melanesians species which have DNA of unknown human species living in South Pacific, northeast of Australia.

According to genetic research, the species are very unlikely to be Neanderthal or Denisovan but could represent a third human relative which are yet to be discovered.

We’re missing a population, or we’re misunderstanding something about the relationships,” Ryan Bohlender, a statistical geneticist from the University of Texas, told Tina Hesman Saey at Science News.

To explain this unknown DNA, the team believes that ancient Melanesians must have bred with a third group of hominids.

Bohlender and his team researched on the percentages of extinct hominid DNA the modern humans carry today, and they have found discrepancies in previous analyses that suggest our mingling with Neanderthals and Denisovans isn’t restricted.

It’s thought that between 60,000 and 100,000 years ago, our ancestors migrated out of Africa, and made contact with other hominid species living on the Eurasian landmass.

In early 2017, researchers investigated certain genetic variants that people of Europe inherited from Neanderthals, and found that they’re associated with several health problems, which includes a slightly increased risk of depression, heart attack, and a number of skin disorders.

By working out the DNA shared by Neanderthals and Denisovans, they calculated that this third extinct human species is likely branched off from their common ancestor 440,000 years ago.

‘Overall, our findings confirm the human family tree is more complicated than we think it is,’ said Dr Bohlender.

He explained: ‘Other archaic populations are likely to have existed, like the Denisovans, who we didn’t know about such as these Melanesians which have traits from a different human species.

Researches have shown that ancient Melanesians pairing with Denisovans may have helped them to adapt to new environments and spread across the Pacific and into Australia.

The evidences are mounting that our interactions with ancient humans were far more complex than we’d assumed. Just because we don’t see them in the fossil record doesn’t mean they did not exist – preserving the remains of something for tens of thousands of years isn’t easy.

Hopefully, the more we investigate the genetic make-up of our most ancestors, the more hints we’ll get of the rich and complicated history our species shared with those that didn’t make it to modern times or made it somehow that’s still hidden!