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The genetic structure of Pacific Islanders.

Friedlaender JS, Friedlaender FR, Reed FA, Kidd KK, Kidd JR, Chambers GK, Lea RA, Loo JH, Koki G, Hodgson JA, Merriwether DA, Weber JL - PLoS Genet. (2008)

Bottom Line: As a result, population relationships there have been open to debate.Neither of these provided an unequivocal signal of phylogenetic relations or population intermixture proportions in the Pacific.Our analysis indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.

View Article: PubMed Central - PubMed

Affiliation: Anthropology Department, Temple University, Philadelphia, Pennsylvania, United States of America. jfriedla@temple.edu

ABSTRACT
Human genetic diversity in the Pacific has not been adequately sampled, particularly in Melanesia. As a result, population relationships there have been open to debate. A genome scan of autosomal markers (687 microsatellites and 203 insertions/deletions) on 952 individuals from 41 Pacific populations now provides the basis for understanding the remarkable nature of Melanesian variation, and for a more accurate comparison of these Pacific populations with previously studied groups from other regions. It also shows how textured human population variation can be in particular circumstances. Genetic diversity within individual Pacific populations is shown to be very low, while differentiation among Melanesian groups is high. Melanesian differentiation varies not only between islands, but also by island size and topographical complexity. The greatest distinctions are among the isolated groups in large island interiors, which are also the most internally homogeneous. The pattern loosely tracks language distinctions. Papuan-speaking groups are the most differentiated, and Austronesian or Oceanic-speaking groups, which tend to live along the coastlines, are more intermixed. A small "Austronesian" genetic signature (always <20%) was detected in less than half the Melanesian groups that speak Austronesian languages, and is entirely lacking in Papuan-speaking groups. Although the Polynesians are also distinctive, they tend to cluster with Micronesians, Taiwan Aborigines, and East Asians, and not Melanesians. These findings contribute to a resolution to the debates over Polynesian origins and their past interactions with Melanesians. With regard to genetics, the earlier studies had heavily relied on the evidence from single locus mitochondrial DNA or Y chromosome variation. Neither of these provided an unequivocal signal of phylogenetic relations or population intermixture proportions in the Pacific. Our analysis indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.

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Pacific Population Structure DetailsIndividual and (below) mean population assignments at K = 10 for the Pacific, HGDP-CEPH East Asia, and French. Purple arrows denote the eight Oceanic-speaking populations with an “Austronesian” assignment signature above 5%. Papuan-speaking group names are in bold italics. Asterisks denote inland groups. Populations are arranged geographically, approximately from west to east.
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pgen-0040019-g007: Pacific Population Structure DetailsIndividual and (below) mean population assignments at K = 10 for the Pacific, HGDP-CEPH East Asia, and French. Purple arrows denote the eight Oceanic-speaking populations with an “Austronesian” assignment signature above 5%. Papuan-speaking group names are in bold italics. Asterisks denote inland groups. Populations are arranged geographically, approximately from west to east.

Mentions: We performed STRUCTURE analyses on a combined East Asia–Pacific dataset to explore in detail the relationships among Melanesians, Polynesians, Taiwan Aborigines, and East Asians, and to clarify the role of intermixture there. The samples included in this analysis were our Pacific set of 40 groups, and from the HGDP-CEPH panel, the “Papuans,” (identified here as “Highlands”), the East Asians, and French (the French were included to identify European admixture). The STRUCTURE results are shown in Figure 6, and the details on their reproducibility in Table S5. At K = 2 and K = 3, the Asia-Pacific clusterings mirrored the first five runs of the global comparison. Bougainville formed a cluster contrasting with central New Britain at K = 3; the New Guinea groups separate at K = 4; and a central New Britain cluster splits at K = 5. Then, at K = 6, a Polynesian cluster appeared, centered on the Mãori, with high ancestral proportions for the Samoan and Micronesian samples as well as the Taiwanese Aborigines. The former “East Asian” ancestral proportion in Melanesian populations converted almost entirely to “Polynesian” in this run. At K = 7, 8, and 9, more Melanesian clusters formed in New Britain and New Ireland. All but one of the Melanesian cluster foci are Papuan-speaking groups, primarily located in the interiors of the large islands (see Figures 7 and 8). The Mamusi, who are Oceanic-speaking neighbors of the Ata, are the exception. There is reason to suspect the Mamusi were originally a Papuan-speaking group (perhaps Ata speakers) who adopted an Oceanic language [34]. At K = 10, the “Europeans” were finally identified as a separate cluster. As shown in Table S5, runs at K = 11 and above became unstable and not reproducible.


The genetic structure of Pacific Islanders.

Friedlaender JS, Friedlaender FR, Reed FA, Kidd KK, Kidd JR, Chambers GK, Lea RA, Loo JH, Koki G, Hodgson JA, Merriwether DA, Weber JL - PLoS Genet. (2008)

Pacific Population Structure DetailsIndividual and (below) mean population assignments at K = 10 for the Pacific, HGDP-CEPH East Asia, and French. Purple arrows denote the eight Oceanic-speaking populations with an “Austronesian” assignment signature above 5%. Papuan-speaking group names are in bold italics. Asterisks denote inland groups. Populations are arranged geographically, approximately from west to east.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2211537&req=5

pgen-0040019-g007: Pacific Population Structure DetailsIndividual and (below) mean population assignments at K = 10 for the Pacific, HGDP-CEPH East Asia, and French. Purple arrows denote the eight Oceanic-speaking populations with an “Austronesian” assignment signature above 5%. Papuan-speaking group names are in bold italics. Asterisks denote inland groups. Populations are arranged geographically, approximately from west to east.
Mentions: We performed STRUCTURE analyses on a combined East Asia–Pacific dataset to explore in detail the relationships among Melanesians, Polynesians, Taiwan Aborigines, and East Asians, and to clarify the role of intermixture there. The samples included in this analysis were our Pacific set of 40 groups, and from the HGDP-CEPH panel, the “Papuans,” (identified here as “Highlands”), the East Asians, and French (the French were included to identify European admixture). The STRUCTURE results are shown in Figure 6, and the details on their reproducibility in Table S5. At K = 2 and K = 3, the Asia-Pacific clusterings mirrored the first five runs of the global comparison. Bougainville formed a cluster contrasting with central New Britain at K = 3; the New Guinea groups separate at K = 4; and a central New Britain cluster splits at K = 5. Then, at K = 6, a Polynesian cluster appeared, centered on the Mãori, with high ancestral proportions for the Samoan and Micronesian samples as well as the Taiwanese Aborigines. The former “East Asian” ancestral proportion in Melanesian populations converted almost entirely to “Polynesian” in this run. At K = 7, 8, and 9, more Melanesian clusters formed in New Britain and New Ireland. All but one of the Melanesian cluster foci are Papuan-speaking groups, primarily located in the interiors of the large islands (see Figures 7 and 8). The Mamusi, who are Oceanic-speaking neighbors of the Ata, are the exception. There is reason to suspect the Mamusi were originally a Papuan-speaking group (perhaps Ata speakers) who adopted an Oceanic language [34]. At K = 10, the “Europeans” were finally identified as a separate cluster. As shown in Table S5, runs at K = 11 and above became unstable and not reproducible.

Bottom Line: As a result, population relationships there have been open to debate.Neither of these provided an unequivocal signal of phylogenetic relations or population intermixture proportions in the Pacific.Our analysis indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.

View Article: PubMed Central - PubMed

Affiliation: Anthropology Department, Temple University, Philadelphia, Pennsylvania, United States of America. jfriedla@temple.edu

ABSTRACT
Human genetic diversity in the Pacific has not been adequately sampled, particularly in Melanesia. As a result, population relationships there have been open to debate. A genome scan of autosomal markers (687 microsatellites and 203 insertions/deletions) on 952 individuals from 41 Pacific populations now provides the basis for understanding the remarkable nature of Melanesian variation, and for a more accurate comparison of these Pacific populations with previously studied groups from other regions. It also shows how textured human population variation can be in particular circumstances. Genetic diversity within individual Pacific populations is shown to be very low, while differentiation among Melanesian groups is high. Melanesian differentiation varies not only between islands, but also by island size and topographical complexity. The greatest distinctions are among the isolated groups in large island interiors, which are also the most internally homogeneous. The pattern loosely tracks language distinctions. Papuan-speaking groups are the most differentiated, and Austronesian or Oceanic-speaking groups, which tend to live along the coastlines, are more intermixed. A small "Austronesian" genetic signature (always <20%) was detected in less than half the Melanesian groups that speak Austronesian languages, and is entirely lacking in Papuan-speaking groups. Although the Polynesians are also distinctive, they tend to cluster with Micronesians, Taiwan Aborigines, and East Asians, and not Melanesians. These findings contribute to a resolution to the debates over Polynesian origins and their past interactions with Melanesians. With regard to genetics, the earlier studies had heavily relied on the evidence from single locus mitochondrial DNA or Y chromosome variation. Neither of these provided an unequivocal signal of phylogenetic relations or population intermixture proportions in the Pacific. Our analysis indicates the ancestors of Polynesians moved through Melanesia relatively rapidly and only intermixed to a very modest degree with the indigenous populations there.

Show MeSH
Related in: MedlinePlus