In this genetical study of crosses between the Australian aborigines and Whites, in which the Áranda (Arunta) tribe at Alice Springs, in the desert heart of Australia, were mostly involved, many families were studied and their physical characters recorded. These include many F1s, also an F2 family and back-crosses to White, to aborigine, and to mixed. These studies provided an exceptionally wide basis for interpretation of the genes. It is evident that reciprocal crosses produce similar results.
Depression of the nasal root, a characteristic of the aboriginal skull, in crosses with the high European nose, probably involves not more than two or three cumulative genes. Sometimes the high, narrow European nose appears to be dominant (Fig. 15). High nasal bridge and narrow nose may be due to linked genes or to genes which affect both height and breadth of the nose. The brow ridges are an equally marked feature of the male skull, but they are frequently absent or much less noticeable in the female, so the manner of inheritance is not yet known. Wide nostrils of the aborigines again appear to depend on a small number of additive genes compared with the narrow nose of the white man. The lips of the aborigines tend to be thick throughout, but generally not everted. Eversion of the lower lip alone, especially in the central part, appears to depend on a single gene effect which is more marked in the homozygous than the heterozygous condition. This gene also occurs in Europeans and is anatomically quite distinct from the everted lips of the Negro.
In Tables I to VII about 15 physical characters are recorded for parents and children. Eye colour, skin colour, hair colour and form, colour of eyelashes and eyebrows, depression of nasal root, sunken orbits, width of nostrils, lips, length and breadth of head, cephalic index, car size and earlobes are included. The colour of hair, eyelashes and eyebrows may all be different in the same individual, the eyelashes tending to be darkest and eyebrows lightest of the three. Hair form ranges from near straight, through wavy to curly, the number of genes involved being very small.
Skin colour of the F1 is remarkably near the white, and when the F1 (male or female) is back-crossed to White the children mostly have white skin (Figs. 15-17). Some are near-white like the F1; but none darker than either parent have been seen. Study of the various crosses leads to the conclusion that a single main gene for melanin in the skin is present in the aborigines, together with a minor gene which alone produces brunet-white skin colour. The aboriginal skin, which is normally reddish mahogany or chocolate brown (not black, except perhaps in some northern tribes), is very subject to tanning (see Fig. 15) and evidently contains much less melanin than the full black Negro skin. The genetics of skin colour in the aborigines is thus very different from that of the African races. Both the skin colour and facial features in the hybrids are much akin to the Caucasian race, substantiating the view of anthropologists that such a relationship exists.
The skull is markedly dolichocephalic and about 20% smaller in cranial capacity than the European. It has two special archaic features — heavy brow ridges and the nasal notch. The latter involves a retreating glabella as well as a depressed root of the nose and sunken orbits. The Mongolian race has the nasal root depressed as in Neandertal man, but no nasal notch. These two, heavy brows and nasal notch, are the most persistent features in aboriginal hybrids. The skull most closely resembles some of the Mount Carmel Neandertaloids with a nasal notch, but the Australian race is neanthropic and not Neandertal, the Neandertals of S. Europe not having the nasal notch, and a low, sloping forehead being exceptional in the aboriginal.
The aborigines, especially those of SE Australia, with relatively hairy bodies, show relations with the Ainu, as well as with the jungle tribes of India. The Negrito element in N. Queensland is considered elsewhere (Gates 1959a). The gene (mutation) for tawny hair, especially in the children, probably originated in Central Australia and may be still spreading. Whether this is from a single event or from repeated mutations is uncertain.
The aborigines are similar to the Papuans in skin colour genetics (published later). Some Papuans show the nasal notch of the Australians. The overhanging nasal tip of the Papuans may occasionally be seen in the Australians. Miscegenation between aborigines and Australians is not a serious problem because (1) the two races are mutually friendly, (2) the number of full-blood aborigines is only 0.5%, (3) the half-caste married to White generally produces children with a white or near-white skin and near-European features.
Archaeological excavations show probably four successive culture levels, the oldest having a radiocarbon date of 8700 years. Whether the earliest entrance of man into Australia was during the last glaciation, when land bridges with New Guinea and Tasmania developed, remains uncertain.