2.3 Genetic Evidence for a Lapita Homeland in Wallacea
23
Lapita colonists to their Moluccan homeland can be seen in the tree worship practised in every Lapita colony. Sacred fig trees with aerial roots (a symbol of contact
between heaven and earth) were transplanted to each colony and worshipped as living embodiments of the Cosmogonic Tree. Lapita tree worship and the survival in
New Zealand and the Chatham Islands of ancient, probably Lapita age, associated
rituals are studied in depth in Chapter 17.
2.3 Genetic Evidence for a Lapita Homeland in Wallacea
Oppenheimer [18] cogently summarizes the human genetic evidence for a
Wallacean indigenous ancestry for the Polynesians. We quote his summary in full
because the prehistory that we propose for the Lapita peoples and for other groups
of Spice Island descent partly depends on this evidence. Oppenheimer explains that
Several genetic marker systems point to a primarily island Southeast Asian ancestry for
Polynesians. The ‘Polynesian motif,’ a unique suite of four single nucleotide polymorphisms in mtDNA, identifies an Oceanic subgroup within a widespread West Asian mtDNA
cluster, known as haplogroup B, and characterized by an intergenic 9-base pair deletion.
This Oceanic subgroup is also the main variant throughout the lowland populations of
coastal Melanesia, and the bio-geographic zone of Wallacea. Most importantly, it is almost
absent to the west of Wallace’s Line. It is not found in the Philippines, Taiwan or China – all
key stations along the Express Train route. Instead, in these regions we find its immediate
ancestor with only three of the four polymorphisms.
The possibility that the final mutation nucleotide 16 247 occurred ‘en route in the
Express Train’ is rendered less likely by a study of the diversity accumulated by the
Polynesian motif in Wallacea and Melanesia to estimate its age using the Molecular clock.
In other words, the motif originated before an express train carrying Taiwanese farmers
could have arrived in Wallacea. This seems to break the train ride somewhere around
Wallacea. . . This finding suggests that Wallacea, a buffer zone between Island Southeast
Asia and Melanesia, might have harbored an ancient, indigenous population (of ultimately
Asian origin) from which the Polynesian colonists emerged. Study of Y-chromosome variation in the region supports a similar conclusion, and indeed earlier autosomal studies
and physical anthropology also suggests ancient differentiation between mainland Asia,
Taiwan, Island Southeast Asia, and Melanesia. It is difficult to reconcile this evidence with
the Express Train-out-of-Taiwan; it seems more consistent with very ancient Austronesian
origins within tropical Island Southeast Asia.
Performing the necessary mathematical calculations for the genetic timing of
the fourth polymorphism of the ‘Polynesian motif’, Richards, Oppenheimer and
Sykes suggest that the mutation occurred, not in Taiwan but in Wallacea and that the
mutation occurred about 17,000 years ago [19]. (Oppenheimer, however, notes in a
later paper that “Wallacea has the oldest estimate for the Polynesian motif at 17,000
years, but this figure has a high standard error. Two independent estimates based on
much larger data sets from New Guinea produce >10,000 years” [20].) Oppenheimer
argues that “The distribution of the final PM genetic innovation places Wallacea as
the likely source of the commonest maternal genotype in lowland Oceania” (p. 597).
In 2004 Oppenheimer proposed a Y chromosome equivalent of the mitochondrial Polynesian motif [20]:
23
Lapita colonists to their Moluccan homeland can be seen in the tree worship practised in every Lapita colony. Sacred fig trees with aerial roots (a symbol of contact
between heaven and earth) were transplanted to each colony and worshipped as living embodiments of the Cosmogonic Tree. Lapita tree worship and the survival in
New Zealand and the Chatham Islands of ancient, probably Lapita age, associated
rituals are studied in depth in Chapter 17.
2.3 Genetic Evidence for a Lapita Homeland in Wallacea
Oppenheimer [18] cogently summarizes the human genetic evidence for a
Wallacean indigenous ancestry for the Polynesians. We quote his summary in full
because the prehistory that we propose for the Lapita peoples and for other groups
of Spice Island descent partly depends on this evidence. Oppenheimer explains that
Several genetic marker systems point to a primarily island Southeast Asian ancestry for
Polynesians. The ‘Polynesian motif,’ a unique suite of four single nucleotide polymorphisms in mtDNA, identifies an Oceanic subgroup within a widespread West Asian mtDNA
cluster, known as haplogroup B, and characterized by an intergenic 9-base pair deletion.
This Oceanic subgroup is also the main variant throughout the lowland populations of
coastal Melanesia, and the bio-geographic zone of Wallacea. Most importantly, it is almost
absent to the west of Wallace’s Line. It is not found in the Philippines, Taiwan or China – all
key stations along the Express Train route. Instead, in these regions we find its immediate
ancestor with only three of the four polymorphisms.
The possibility that the final mutation nucleotide 16 247 occurred ‘en route in the
Express Train’ is rendered less likely by a study of the diversity accumulated by the
Polynesian motif in Wallacea and Melanesia to estimate its age using the Molecular clock.
In other words, the motif originated before an express train carrying Taiwanese farmers
could have arrived in Wallacea. This seems to break the train ride somewhere around
Wallacea. . . This finding suggests that Wallacea, a buffer zone between Island Southeast
Asia and Melanesia, might have harbored an ancient, indigenous population (of ultimately
Asian origin) from which the Polynesian colonists emerged. Study of Y-chromosome variation in the region supports a similar conclusion, and indeed earlier autosomal studies
and physical anthropology also suggests ancient differentiation between mainland Asia,
Taiwan, Island Southeast Asia, and Melanesia. It is difficult to reconcile this evidence with
the Express Train-out-of-Taiwan; it seems more consistent with very ancient Austronesian
origins within tropical Island Southeast Asia.
Performing the necessary mathematical calculations for the genetic timing of
the fourth polymorphism of the ‘Polynesian motif’, Richards, Oppenheimer and
Sykes suggest that the mutation occurred, not in Taiwan but in Wallacea and that the
mutation occurred about 17,000 years ago [19]. (Oppenheimer, however, notes in a
later paper that “Wallacea has the oldest estimate for the Polynesian motif at 17,000
years, but this figure has a high standard error. Two independent estimates based on
much larger data sets from New Guinea produce >10,000 years” [20].) Oppenheimer
argues that “The distribution of the final PM genetic innovation places Wallacea as
the likely source of the commonest maternal genotype in lowland Oceania” (p. 597).
In 2004 Oppenheimer proposed a Y chromosome equivalent of the mitochondrial Polynesian motif [20]: