When describing the species in 2002, Brunet "et al." noted the combination of features which would be considered archaic or derived for a species on the human line (the tribe Hominina), the latter namely bipedal locomotion and reduced canine teeth, which they interpreted as evidence of its position near the chimpanzee–human last common ancestor (CHLCA). This classification made "Sahelanthropus" the oldest Hominina, shifting the centre of origin for the clade away from East Africa. They also suggested that "Sahelanthropus" could be a sister group to the 5.5 to 4.5 million year old "Ardipithecus" and later Hominina. The classification of "Sahelanthropus" in Hominina, as well as "Ardipithecus" and the 6 million year old "Orrorin", was at odds with molecular analyses of the time which had placed the CHLCA between 6 and 4 million years ago based on a high mutation rate of about 70 mutations per generation. All these genera were anatomically too derived to represent a basal hominin (the group containing chimps and humans), so molecular data would only permit their classification into more ancient and now-extinct lineages. This was overturned in 2012 by geneticists Aylwyn Scally and Richard Durbin who studied the genomes of children and their parents and found the mutation was actually half that, placing the CHLCA anywhere from 14 to 7 million years ago, though most geneticists and palaeoanthropologists use 8 to 7 million years ago.