This undated photo provided by Madrid Scientific Films in December 2013 shows the skeleton of a hominin estimated to be about 400,000-years-old, excavated from Sima de los Huesos, Spain. Scientists have reached farther back than ever into the ancestry of humans to recover and analyze DNA, with a sample from bones from the site in northern Spain. So far, the achievement has provided more questions than answers about the human family tree. Results were presented online Wednesday, Dec. 4, 2013 in the journal Nature by Matthias Meyer and colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, with co-authors in Spain and China. (AP Photo/Madrid Scientific Films, Javier Trueba)
