Genetic studies in the Markham Valley, northeastern Papua New Guinea: Gamma globulin (Gm and Inv), group specific component (Gc) and ceruloplasmin (Cp) typing†

Genetic studies in the Markham Valley, northeastern Papua New Guinea: Gamma globulin (Gm and Inv), group specific component (Gc) and ceruloplasmin (Cp) typing. M. S. Schanfield, Eugene Giles and H. Gershowitz, Department of Human Genetics, University of Michigan, Ann Arbor, Michigan 48104. Immunoglobulin allotyping was carried out on 680 serum samples from inhabitants of the Markham Valley, Papua New Guinea (seven villages speaking the same Melanesian [MN] language and a single Papuan [PAP] speaking village). Family and population data verified the presence of Gmag, and Gmafb among the MN speakers and Gmag, Gmaxg, Gmab and Gmafb among the PAP speakers. The frequency of Gmag was between 0.048 and 0.235, while the frequency of Gmab was between 0.427 and 0.627 and the frequency of Gmafb ranged between 0.261 and 0.424 among the seven MN villages; the single PAP village had frequencies of 0.568, 0.160, 0.213 and 0.059 for Gmag, Gmaxg, Gmab and Gmafb respectively. The frequency of Inv1 ranged between 0.034 and 0.095 in the MN villages and 0.014 in the PAP village. The rare occurrence of Gm(x) without Gm(g) could be studied in three families. In an MN family the presence of Gm(x) without Gm(g) was explained by the presence of a Gmaxfb haplotype, while in two PAP families the presence of Gm(x) without Gm(g) was explained by the abnormally weak expression of Gm(g) in a Gmaxg haplotype. A total of 654 sera were typed for Gc, with the seven MN villages ranging between 0.350 and 0.650 for Gc1, 0.312 and 0.575 for Gc2 and between 0.017 and 0.112 for GcAb; the single PAP village had a value of 0.627 for Gc1, 0.165 for Gc2 and 0.208 for GcAb. A total of 693 sera were tested for ceruloplasmin type. All showed the common Cp(b) phenotype.