Study uncovers hidden ancient human lineage in DNA of all modern peoples
Researchers using a new computational method have identified DNA from an unknown archaic hominin in every modern human population, a lineage that left no fossil record.
Scientists have devised a novel algorithm called TRACE to trace archaic genetic input using only present-day human DNA. Co-led by computational biologist Yulin Zhang of UC Berkeley and geneticist Arjun Biddanda of Johns Hopkins, the study examined 503 contemporary genomes from across the globe. While confirming that roughly 2% of non-African DNA derives from known Neanderthal and Denisovan sources, the analysis also revealed a previously unrecognized “ghost” lineage contributing between 0.5% and 1% of the genome in every population studied.
This lineage likely split from the human branch more than half a million years ago, contemporaneous with Neanderthals and Denisovans, and appears even in genomic regions once thought to be solely modern. Population geneticist Priya Moorjani highlighted the surprise of finding ghost ancestry in such regions, including near the speech-related FOXP2 gene. Computational biologist Patrick F. Reilly, not involved in the work, cautioned that false positives are possible and suggested further cross-method verification. Future confirmation may rely on additional computational tools or the rare recovery of ancient DNA from sub-Saharan Africa.
Why it matters
The discovery suggests human evolution involved more interbreeding with unknown groups than previously thought.
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