The Gerbich-negative blood group types are rare in most populations, but reach appreciable frequencies in certain Melanesian groups in Papua New Guinea. The recent cloning of the human glycophorin C (GPC) gene, that encodes Gerbich (Ge) blood group antigens, has facilitated study of its genetic variants. We have obtained partial genomic clones of a normal GPC gene, for molecular analysis of Ge: -1, -2, -3 types in Melanesians, and have shown that a 3.5 kb deletion in the GPC gene that removes all of exon 3 accounts for at least one Gerbich-negative phenotype in Melanesians. Population distributions of GPC RFLP have shown that the deletion-type GPC is not confined to mainland Papua New Guinea as previously thought, but occurs sporadically in Melanesians from Fiji as well as in Micronesians.