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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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Related in: MedlinePlus

Pacific Population TreeNeighbor-joining FST-based tree for 687 microsatellites from the Pacific, East Asia, and French populations, with the range of bootstrap values indicated by branch thicknesses. Colors are the same as in the STRUCTURE analysis at K = 10. New Britain populations are circled. Papuan-speaking groups are in bold italics; inland groups in Melanesia have asterisks. Abbreviated names are spelled out in Table S1.
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pgen-0040019-g009: Pacific Population TreeNeighbor-joining FST-based tree for 687 microsatellites from the Pacific, East Asia, and French populations, with the range of bootstrap values indicated by branch thicknesses. Colors are the same as in the STRUCTURE analysis at K = 10. New Britain populations are circled. Papuan-speaking groups are in bold italics; inland groups in Melanesia have asterisks. Abbreviated names are spelled out in Table S1.

Mentions: Figure 9 shows the unrooted neighbor-joining tree for the East Asia–Pacific populations from a pairwise FST coancestry distance matrix for 687 microsatellites (the pairwise FST values are in Table S7). Bootstrap values for the branches, generated with the PHYLIP program from population allele frequencies for 100 different trees, are indicated by branch thicknesses. As shown, most of the trunk elements had high bootstrap values, as did a number of branches within Northern Island Melanesian groups. By contrast, the mainland East Asian group relationships were considerably more ambiguous, their branches were shorter, and only the Taiwan Aborigines had a strong internal branch. The tree branching again closely reflected the clustering in STRUCTURE, indicated by the corresponding colors from K = 10. The populations with the longest branches were those with the largest ancestral proportions assigned to single STRUCTURE clusters, and had the lowest heterozygosities. These populations tend to be Papuan-speaking groups in island interiors. The STRUCTURE analysis specifies the role and nature of admixture in a way that a population-based tree cannot.


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 TreeNeighbor-joining FST-based tree for 687 microsatellites from the Pacific, East Asia, and French populations, with the range of bootstrap values indicated by branch thicknesses. Colors are the same as in the STRUCTURE analysis at K = 10. New Britain populations are circled. Papuan-speaking groups are in bold italics; inland groups in Melanesia have asterisks. Abbreviated names are spelled out in Table S1.
© Copyright Policy
Related In: Results  -  Collection

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

pgen-0040019-g009: Pacific Population TreeNeighbor-joining FST-based tree for 687 microsatellites from the Pacific, East Asia, and French populations, with the range of bootstrap values indicated by branch thicknesses. Colors are the same as in the STRUCTURE analysis at K = 10. New Britain populations are circled. Papuan-speaking groups are in bold italics; inland groups in Melanesia have asterisks. Abbreviated names are spelled out in Table S1.
Mentions: Figure 9 shows the unrooted neighbor-joining tree for the East Asia–Pacific populations from a pairwise FST coancestry distance matrix for 687 microsatellites (the pairwise FST values are in Table S7). Bootstrap values for the branches, generated with the PHYLIP program from population allele frequencies for 100 different trees, are indicated by branch thicknesses. As shown, most of the trunk elements had high bootstrap values, as did a number of branches within Northern Island Melanesian groups. By contrast, the mainland East Asian group relationships were considerably more ambiguous, their branches were shorter, and only the Taiwan Aborigines had a strong internal branch. The tree branching again closely reflected the clustering in STRUCTURE, indicated by the corresponding colors from K = 10. The populations with the longest branches were those with the largest ancestral proportions assigned to single STRUCTURE clusters, and had the lowest heterozygosities. These populations tend to be Papuan-speaking groups in island interiors. The STRUCTURE analysis specifies the role and nature of admixture in a way that a population-based tree cannot.

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