In this entry, rather than discussing Polynesians alone, which seem to be just the tip of the Eastern Austronesian iceberg, I'll try to understand here the complexity of speakers of Oceanic languages, the main native language family of Island Oceania.
Oceanic is a branch of Austronesian but for the purposes of this entry we will only mention other Austronesian peoples/languages tangentially. The focus is Oceanic because we can't understand the parts without the whole here most probably.
Oceanic languages are scattered as follows:
Black enclosed zones are pockets of languages from other families.
(CC by kwami)
It is certainly interesting that Micronesian and Fijian-Polynesian seem to be particularly related among them. Instead the Western Oceanic and Admiralty subfamilies (both from the islands near Papua) seem to have separated early on or diverged farther for whatever other reasons (stronger substrate influence for example).
|Lapita pot from Tonga (source)|
As I cited recently, Polynesians seem to have spread from Society Islands in the 1190-1290 CE window. The genesis of the Micronesian family is not well understood... but the overall genesis of Oceanic languages seems to be at the Lapita culture, which spread through Island Melanesia (excluding Papua) and some nearby islands (notably Tonga and Samoa - also Marquesas c. 300 CE(ref)).
Early Lapita culture is dated to c. 1350-750 BCE, while a Late phase is dated to c. 250 BCE, spreading to the Solomon Islands, which show no indications of the earlier period (Ricaut 2010, fig. 2).
So a simplified chronology for Oceanic expansion would be
- Lapita culture from near Melanesia to Vanuatu and Kanaky (New Caledonia), then to:
- Fiji, Samoa and Tonga since c. 900 BCE
- Solomon Is. c. 250 BCE
- Arrival to Society Islands (Tahiti, etc.) c. 300-800 CE from maybe Samoa.
- Main Polynesian expansion to the farthest islands (Hawaii, Rapa Nui, Aotearoa-NZ) c. 1200 CE from Society Is.
A classical and unavoidable element in the ethnographic division of the region is phenotype, appearance (i.e. 'race'). Since the first European arrival to the area the division between black Melanesians and white Polynesians (very relative as we will see now) has been part of all our conceptualizations of the region.
Conscious of that and wanting to get a better impression I collected from the Internet what I estimate may be representative faces from the Oceanic linguistic zone and nearby areas (other Austronesians and Melanesians) and put them on a map:
|Click to expand|
A relatively homogeneous Polynesian phenotype can be identified and one can imagine that it stems from the area of Samoa-Tonga, considering the previous prehistorical review. But otherwise the diversity, gradations and abundance of local uniqueness seems quite impressive.
Based on other cases, one would imagine also that phenotype differences would be coincidental with genetic ones. However this is not too easy to discern, partly because Polynesians have strong founder effects that blur the matter, partly because there is no obvious strict dividing line between the various phenotypes and partly because of the insistence of some in considering Lapita as a Polynesian phenomenon, when it is obviously an Oceanic one, including and emphasizing the Melanesian side of the diverse Oceanic landscape, of which the Polynesian-Micronesian branch is just one element (famous and extended but not the core).
The main Y-DNA lineage among Polynesians is C2a1 (P33), not found outside Polynesia senso stricto but reaching there frequencies of 63-90% (excepted Tonga where it's only 33%). This is a clear founder effect in this population.
|C subclades in SE Asia and Oceania|
(from Karafet 2010, annotated with ISOGG nomenclature)
C2a1 is clearly derived from a Melanesian superset C2a (M208) still found as C2a(xC2a1) at low frequencies in Samoa (8%) and Tahiti (4%) but also in Vanuatu (2%) and coastal Papua (13%). C2a establishes a probably genetic link of Polynesians with Lapita culture and Melanesian peoples in general.
An earlier pylogenetic stage is C2 (M38), which is probably in the region since the very first colonization process some 50 thousand years ago (or maybe even earlier). C2(xC2a) is most common in Wallacea (East Indonesia, East Timor), where it reaches maybe figures of 33% on average. It is however also found in highland Papua (13%) and Vanuatu (20%) but as it is most doubtful that C2a evolved as recently as Lapita times, we should really focus on C2a as such rather than the wider C2, which only seems to confuse the matter.
The lack of C2(xC2a) in most of the Oceanic languages' area clearly indicates that the expansion (and subsequent founder effects) did not begin in Wallacea but in Melanesia, at least in what regards to C sublineages.
The other major Polynesian haplogroup is O3a2 (P201), which would seem to have originated in Philippines and maybe arrived there via Micronesia:
|O3 subclades in SE Asia and Oceania|
(from Karafet 2010, annotated with ISOGG nomenclature)
Melanesian populations also sport some lineages that are not common among other Oceanic-speaker peoples, notably K, M and S. However they are irregularly shared with Wallacea (Eastern Indonesia, East Timor). Like C2 these lineages coalesced in the region soon after colonization by Homo sapiens.
In the motherly side of things genetic, the absolutely dominant mtDNA lineage among Polynesians (the so-called Polynesian motif) is B4a1a1, which ultimately stems from East or rather SE Asia. However it probably arrived to the region (again) via Melanesia, albeit maybe somewhat tangentially.
The matrilineal Polynesian motif does offer a possible pattern of settlement, maybe related specifically to Late Lapita, that could allow us to understand the possible origin of the phenotype differences between Melanesians and Polynesians, as could do the Y-DNA lineage O3a2. However there are lots of remnants of quite strictly Melanesian Early Lapita, as is evident by the (Y-DNA) C2a lineages retained so strongly among Polynesians within their own founder effects, whose importance we cannot afford to dismiss.
Other mtDNA lineages like Q1 or M27 are of relevance in Melanesian populations. Q1 did make its way into some Polynesian populations but as minority lineage only.
Update (Oct 31):
Terry in the comments sections grunts a lot but now and then provides useful complementary data, for example this Y-DNA map of the region from Kayser 2006:
|Kayser 2006 - fig. 1|
Frequency distribution of (A, B) NRY and (C, D) mtDNA haplogroups found in Polynesia with a genetic origin in (A, C) Asia or (B, D) Melanesia.
As is apparent since Kayser's publication (if not before), the Melanesian patrilineages are much more common (actually dominant) among Polynesians than the matrilineages from the same origin, what is attributable to a founder effect related to the Lapita culture.
Another interesting reference is this Y-DNA map of Papua (New Guinea) and some nearby islands (from Mona 2007):
Both maps and/or the data in the relevant papers provide key information on possible origins for the C2a-M208 patrilineal founder effect, so important in general in the Oceanic peoples and specially the Polynesian branch. The exact origin cannot be pinpointed without further research (or maybe not at all) but it's clear that C2a-M208 only exists from Papua (New Guinea) to the East, so it must have a Melanesian origin be it Papuan or from the nearby islands.
- François-Xavier Ricaut et al., Ancient Solomon Islands mtDNA: assessing Holocene settlement and the impact of European contact. Journal of Archaeological Science, 2010 ··> LINK (PDF).
- Jonathan S. Friedlaender et al., Melanesian mtDNA Complexity. PLoS ONE, 2007 ··> LINK (open access).
- Tatiana Karafet et al., Major East-West Division Underlies Y Chromosome Stratification Across Indonesia. MBE 2010 ··> LINK (free access).
- Michael Knapp et al., Complete mitochondrial DNA genome sequences from the first New Zealanders. PNAS 2012 ··> LINK (open access).
- Manfred Kayser et al., Melanesian and Asian Origins of Polynesians: mtDNA and Y Chromosome Gradients Across the Pacific. MBE 2006 ··> LINK (open access).
- Stephano Mona et al., Patterns of Y-Chromosome Diversity Intersect with the Trans-New Guinea Hypothesis. MBE 2007 ··> LINK (free access).
Note: updates after first posted version in maroon color.