A new paper published in Nature Genetics (behind a paywall, unfortunately) shows how that fact enables the genomes of long-dead ancestors to be reconstructed, using just the DNA of their descendants.

As an article in Futurism explains, the unique circumstances of the individual chosen for the reconstruction, the Icelander Hans Jonatan, aided the research team as they sought to piece together his genome nearly two centuries after his death in 1827. The scientists mainly came from the Icelandic company deCODE Genetics, one of the pioneers in the world of genomics, and highly-familiar with Iceland‘s unique genetic resources.