As with the linguistic evidence, genetic studies are treated elsewhere in this volume. For many of the more recently discovered genetic systems, sample coverage is spotty compared to that in archaeology and linguistics. For example, there has not been a great deal of work in the Bismarcks, an area critical for comparison with the archaeological and linguistic pictures. Many of the genetic data were collected for purposes of applied medical rather than historical research and this should also be remembered. That said, the genetic prehistory established so far does seem consonant with the prehistories derived from the other two disciplines.

If we start with Polynesia and work backwards, the pattern is clearer. Initial settlement of Polynesia by the Lapita culture and lack of evidence for any but Polynesian sub-group languages there would suggest Polynesians, a genetically homogeneous group, are direct descendants of the bearers of Lapita culture. An ultimate origin in Island Southeast Asia for the “Pre-Polynesians” now seems certain, with some evidence of genetic admixture with populations in northern Island Melanesia, as summarized by Serjeantson and Hill:

The lack of particular coastal New Guinea [genetic] markers in Polynesians, such as the high-frequency –α^4.2 thalassaemia deletion, the albumin NG variant, the HLA-B13.Cw4 haplotype, and the B allele of the ABO blood group, all argue that the pre-Polynesians moved rapidly through this part of Melanesia. However, the presence of a substantial frequency of the Melanesian α-globin haplotypes IIIa and IVa in all Polynesians indicates that at some point there was significant interbreeding with Melanesians. The presence of the –α^3.7III but not the –α^4.2 α thalassaemia deletion indicates that this contact was probably mainly in northern island Melanesia rather than in New Guinea (1989:287-288).

Not all bearers of the Lapita culture moved to Polynesia of course. The genes of the “stay at homes” can be found in coastal and island Melanesian groups who are genetically the descendants both of the pre-Lapita populations in the area and of the intrusive Southeast Asian populations who also gave rise to the Polynesians. The latest evidence indicates that Fijians have undergone admixture with Island Melanesians since first settlement by Lapita groups, thus reinstating an earlier and partly discredited view of Fijian culture history (Serjeantson and Hill 1989:288-289). The original Fijian population would have been more Polynesian in appearance. This might also have been true of the initial settlers of Vanuatu and New Caledonia. The new genetic evidence is also against any direct link between Polynesians and Micronesians. Micronesian populations are diverse but in general are a distinct Island Southeast Asian population with genetic input from Melanesia in varying degrees (Serjeantson and Hill 1989:290-291). Polynesian populations cannot be derived from Micronesia, as Howells (1973) once believed.

Thus there may have been a moment in the Bismarcks when there was a single people using Lapita pottery, genetically, linguistically and culturally distinct from their neighbours. But this unity and distinctiveness would have been shortlived. Lapita-using populations which spread to Polynesia and those in Island Melanesia subsequently had divergent genetic and linguistic histories. The end of Lapita culture in these two areas also meant very different things. In Island Melanesia rapid transformations in material and other aspects of culture occurred, previous An languages in parts of the Bismarcks and Northern Solomons were replaced by languages of Western Oceanic An-type, and there was perhaps another phase of migration through Island Melanesia of Bismarcks area populations which further swamped the “pre-Polynesian” genotypes. In Polynesia seemingly more gradual changes occurred to produce the cultures of the area recorded in the recent past, their An languages conservative and their art forms still clearly recognizable as Lapita-derived.^[2] Their homogeneous physical type compared to the more differentiated populations of Island Melanesia bears witness to these developments having occurred in comparative isolation.