The ethnological significance of the gamma-globulin (Gm) factors in melanesia.

Abstract

AbstractA study was made of the distribution of the immunoglobulin markers Gm(a), (x), (z), (f), (g), (b0), (b1), (b3), (s), (t), (c3), (c5) and Inv (1) and Inv (a) in 906 individuals sampled from several population groups living in various parts of New Guinea and New Britain. A study of 123 families confirmed the presence of the following gene complexes: Gmza;g, Gmzax;g, Gmza;b and Gmfa;b. Gm(s), (t), (c3) and (c5) were absent and either all or none of Gm(b0), (b1) and (b3) present. Striking differences occurred in the geographical and ethnic distribution of the Gm gene complexes. Gmfa;g was either absent or in very low frequency, and Gmza;b, Gmzax;g and Gmza;g were present in varying frequencies in both the highland and western coastal populations in the mainland of New Guinea. All of these populations spoke non‐Austronesian languages. On the other hand Gmfa;b was present in the Melanesian‐speaking Motu of the Central District of the mainland, in the Melanesian‐speaking Tolai and the non‐Austronesian‐speaking Sulka and Baining of the island of New Britain. It is suggested that Gmfa;b and Gmza;b are respectively Malayo‐Polynesian and pre‐Austronesian markers, although a clear cut distinction between modern populations derived from these stocks is often blurred by the effects of gene flow and drift.Considerable ethnic and geographical variation was also found in the distribution of Inv(1) and Inv(a). In two Highland NAN‐speaking populations the Inv(1+a+) phenotype percentages were 1.0 and 5.4, whilst percentages ranging from 0.0 to 56.4% were found for coastal MN‐speaking populations. The percentages of Inv(1+a+) in the total MN‐ and NAN‐speaking populations were 31.6 and 10.0 respectively.