Overview
- A UC Berkeley team published a study in Science on July 30 reporting computational evidence that at least two previously unknown archaic hominin lineages left DNA in living people.
- The researchers used a new genealogical method called TRACE to scan more than 500 modern genomes and recovered known Neanderthal and Denisovan segments as validation of the approach.
- One detected ‘‘ghost’’ introgression diverged about 800,000 years ago and contributes roughly 1 percent of ancestry across present-day populations, implying the gene flow predates the main out‑of‑Africa expansion.
- A separate, much older ‘‘super‑archaic’’ lineage—dating to around 1.8 million years—appears only inside Denisovan-derived regions in Oceanian genomes, consistent with indirect transfer via Denisovan interbreeding.
- Key details remain unresolved: the exact identities of the ghost groups, precise dates and places of mixing, and any functional effects on immunity, metabolism or other traits will need ancient genomes and independent replication to confirm.