Fossil evidence is used to support the regional continuity model. Its advocates claim that there has been a continuity of some anatomical traits from archaic Homo sapiens to modern humans in Europe and Asia. In other words, the Asian and European physical characteristics have antiquity in these regions going back over 100,000 years. They point to the fact that many Europeans have relatively heavy brow ridges reminiscent of Neandertals. Similarly, it is claimed that Chinese facial characteristics can be seen in Asian archaic Homo sapiens dating to 200,000 years ago. Like Homo erectus, East Asians today commonly have shovel-shaped incisors while Africans and Europeans rarely do. This supports the contention of direct genetic links between Asian Homo erectus and modern Asians. Alan Thorne of the Australian National University believes that Australian aborigines share key skeletal and dental traits with people who inhabited Indonesia at least 100,000 years ago. The implication is that there was no replacement by modern humans from Africa 50,000 years ago. However, the evidence does not rule out gene flow from African populations to Europe and Asia at that time and before. David Frayer of the University of Kansas believes that a number of European fossils from the last 50,000 years have characteristics that are the result of archaic and modern Homo sapiens interbreeding.