A ball of 4,000-year-old hair frozen in time tangled around a whalebone comb led to the first ever reconstruction of an ancient human genome a decade ago. The hair, which was preserved in arctic permafrost in Greenland, was collected in the 1980s. It wasn’t until 2010 that evolutionary biologists were able to use pioneering shotgun DNA sequencing to reconstruct the genetic history of the hair. It sparked a ‘decade of discovery.’