Eskimo people are culturally and biologically distinguishable from neighbouring indigenous groups including American Indians and the Sami of northern Europe. Studies comparing Eskimo-Aleut languages to other indigenous North American languages indicate that the former arose separately from the latter. Physiologically, an appreciable percentage of Eskimo people have the B blood type (ABO system), which seems to be absent from other indigenous American groups. Because blood type is a very stable hereditary trait, it is believed that at least a part of the Eskimo population is of a different origin from other indigenous American peoples.