Two Strangers Are Living in Your DNA

The part of your genome that scientists believed was most distinctly, irreducibly you just turned out to harbor something else entirely.

The ghost lineage's fingerprints turned up inside FOXP2, the gene linked to speech and language, a stretch of the genome largely free of Neanderthal or Denisovan ancestry and long assumed to be purely modern-human territory. In some of the genomes the team analyzed, roughly 13 percent of that region traced back to the ghost lineage instead. The stretch held up as proof of what makes us unique turned out to have company all along.

A new study published in Science reports that modern humans carry DNA traces from two previously unidentified ancient human populations: a "ghost" lineage and a much older "super-archaic" lineage. Neither has a fossil record we can match. Neither has a sequenced genome. We know they existed because they are, in pieces, still here.

The ghost lineage interbred with modern humans in Africa before the most recent migration out of Africa some 50,000 years ago. Those genes comprise around 1 percent of modern human genomes, comparable to the amount of Neanderthal DNA most people carry. The super-archaic lineage had already branched off from other hominins around 1.8 million years ago and probably interbred with Denisovans in Eurasia before those fragments found their way into modern humans through later mixing.

The team's new method, called TRACE, needs only present-day genomes to spot these signals, no ancient DNA required. Running it against genomes from more populations could turn up still more hidden relatives, the researchers say.

Human evolution, it turns out, was less a branching tree and more a long series of encounters between groups who had every reason not to exist in the same place at the same time, and yet apparently managed it repeatedly.

Read the full story at Discover Magazine, July 31, 2026

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