Researchers have read strands of ancient DNA teased from the thigh bone of an early human that died 400,000 years ago in what is now northern Spain. The genetic material was pieced together from a clutch of cells found in bone fragments – the oldest human remains ever to yield their genetic code. The work deepens understanding of the genetics of human evolution by some 200,000 years, raising hopes that researchers can build a clearer picture of the earliest branches of the human family tree by studying the genetic make-up of fossilised remains dug up elsewhere.