Scientists Found DNA from Not One, but Two ‘Ghost Species’ Hiding in Our Genetic Code

Key Points:

• UC Berkeley researchers developed a new framework called TRACE to identify regions of the human genome containing super-archaic "ghost" DNA, distinct from Neanderthal or Denisovan ancestry.
• Their study found evidence of at least one ghost lineage contributing about 1% of DNA to all modern human populations, predating the out-of-Africa expansion and diverging around the time humans split from Neanderthals.
• This ghost DNA likely entered the Homo sapiens genome through introgression approximately 300,000 years ago, with multiple unidentified archaic hominin lineages influencing human ancestry.
• Although the exact identity of these ghost species remains unknown, researchers speculate they could be Homo erectus, Homo heidelbergensis, or other yet-undiscovered hominins missing from the fossil record.
• Future research with additional ancient genomes, especially from Africa and Asia, is needed to clarify the timing, sources, and evolutionary impact of these archaic gene contributions on human immunity and metabolism.