Buried within the genomes of every living human are faint but measurable traces of people who vanished long before history began — not the Neanderthals or Denisovans we have come to know, but two entirely unnamed lineages whose existence was only legible through the mathematics of inheritance. Researchers at UC Berkeley, using a computational method called TRACE, have read backward through time in the DNA of hundreds of living people and found genetic signatures pointing to a ghost ancestor who walked alongside our forebears in Africa more than 50,000 years ago, and a super-archaic population