Figure 1.
Colors show interior vs. coastal locations: blue for coastal; red for interior; green for intermediate locations. The Nakanai are represented by both a coastal and an interior population. Filled shading vs. open shapes show language affiliation: Oceanic languages are filled; Papuan languages are open. Shapes show island location: diamonds for New Britain; squares for Bougainville; circles for New Ireland, New Hanover, and Mussau. Numbers are waypoints used to estimate geographic distances between populations on New Britain and between populations on New Britain and other islands.
Table 1.
Sample details.
Figure 2.
Population history for the branching model simulations.
The first division is between Oceanic and Papuan languages, and subsequent splits occur in a nested fashion between and within each island. In the simulations, there is no migration between any populations.
Figure 3.
Simulated and observed heat plots for the branching model.
The heat plots are color-coded representations of the square matrix of within- and between-population allelic identities. The level of allelic identity is indicated by the color-scale at the bottom of each plot. The diagonals represent the within population allelic identities, and the off-diagonals represent the between-population identities. Population names are located above and to the left of the matrix. The Oceanic-speaking populations are shaded in gray. (A,B) The populations are clustered first by language group, then by island. (B) The circled population groupings have high allelic identity even though the populations are in different language groups. (C) The populations are clustered only by island and neighborhood.
Figure 4.
(A) Language tree. (B) Genetic tree. (C) Revised language tree after removing outliers. The symbols and colors associated with the population names are the same as those used in Figure 1. Bootstrap values for the language tree and revised language tree are listed next to each branch. Because there was insufficient room to list the numeric values next to many of the small branches in the genetic tree, bootstrap values in those cases are indicated by the branch color. The outlier populations identified from the observed vs. expected genetic distance plots (Figure 5) are highlighted with yellow circles. These populations are absent from the revised language tree. The genetic tree contains more populations than the language tree because biological samples were collected from several populations that spoke the same language (e.g., the genetic sample contains two Anêm-speaking populations).
Figure 5.
Plots of observed distances estimated from the microsatellites vs. the expected genetic distances estimated for the baseline and language trees.
R-squared values are indicated on the plots. (A) Comparison of the observed genetic distances with predicted distances for the baseline tree. (B) Comparison of the observed genetic distances with predicted distances for the language tree. The bottom figure highlights the Kol vs. other population comparisons. (C) Comparison of the observed genetic distances with predicted distances for the revised language tree (outlier populations removed). The bottom figure highlights the Mali vs. other population comparisons.
Table 2.
Λ values for the baseline and language trees.
Table 3.
Comparison of fit of various models to the baseline and language trees.
Table 4.
Reduction in model Λ after sequential removal of major outlier populations.
Figure 6.
Simulated isolation by distance heat plot.
Additional isolation by distance results are shown in Text S1.
Table 5.
Correlations of genetic, linguistic and geographic distances in the full sample and in localized geographic and linguistic subsets.
Figure 7.
Plots of genetic, linguistic, and geographic distance comparisons.
Coastal vs. coastal (red circles) and interior vs. interior (blue circles) are highlighted in the plots on the left. Blue squares highlight the interior New Britain comparisons. Oceanic vs. Oceanic (red circles) and Papuan vs. Papuan (blue circles) comparisons are highlighted in the plots on the right. (A,B) Genetic vs. geographic distance plots. (C,D) Linguistic vs. geographic distance plots. (E,F) Linguistic vs. genetic distance plots.
Table 6.
Correlations of genetic, linguistic, and geographic distances with interior Oceanic- and Coastal Papuan-speaking populations removed.