Some modern humans share a genetic variant with extinct human relatives called Denisovans . New research, however, suggests our archaic cousins may have been the conduit for genetic material from another, surprising species. In a study published today in the journal Nature, researchers extracted enamel proteins from the teeth of six Homo erectus individuals. They found two amino acid (the building blocks of proteins) variants in all six teeth, including one that researchers know also existed in Denisovans and exists today in some modern humans. Simply put, the study indicates that H. erectus hanky-pankied with Denisovans, who hanky-pankied with Homo sapiens,  and here we are now. Three human species Katerina Harvati-Papatheodorou , director of paleoanthropology at the Eberhard Karls University of Tübingen who was not involved in the study, tells Gizmodo that the study is “very exciting” and “sheds important light on relationships between H. erectus and Denisovans,” which have been hard to evaluate.…