Scientists retrieved 800,000-year-old proteins from Homo antecessor tooth enamel. Mass spectrometry sequenced ancient dental proteins. Homo antecessor shares close relationship with Homo sapiens, Neanderthals, Denisovans. Homo antecessor is sister lineage to group of modern humans, Neanderthals, Denisovans. Features shared with these hominins appeared earlier than thought. Initial fossils suggested Homo antecessor as common ancestor to sapiens and Neanderthals. Facial features of Homo antecessor similar to Homo sapiens, unlike Neanderthals. Palaeoproteomics overcomes DNA degradation limits beyond 400,000 years. Method reconstructs human family tree further back. Human-chimp split occurred 9-7 million years ago. Fossils from Gran Dolina cave, Sierra de Atapuerca, Spain. Protein analysis confirms population relationships among hominins. Homo antecessor basal to emerging humanity of Neanderthals, Denisovans, sapiens.