Figure 1.
Geographic origin of ancient samples and ADMIXTURE results.
(A) Map of Europe indicating the discovery sites for each of the ancient samples used in this study. (B) Ancestral population clusters inferred using ADMIXTURE on the HGDP dataset, for k = 6 ancestral clusters. The width of the bars of the ancient samples was increased to aid visualization.
Table 1.
Summary of datasets.
Figure 2.
Allele sharing and D-tests with whole-genome datasets.
(A) Normalized derived allele sharing rate of the Iceman with Eurasian whole genomes from Complete Genomics. Each circle represents the rate of sharing with a particular genome, grouped by population of origin. Positions on the y-axis have added jitter for ease of visualization. Populations with EUR suffix correspond to the European ancestry tracts of individuals of populations with known European admixture (ASW, MXL). Due to differences in admixture proportions among individuals from those populations, the total number of observations varies between individuals, indicated by the size of the circles. (B) D-test results for the ancient samples compared to populations from the 1000 Genomes project and Sardinia. Each panel shows results for a particular ancient sample, grouped by cultural context. Diamonds indicates the value of the D-statistic for a single D-test involving the ancient sample and a pair of modern populations, shown on the left and right of the panels. Significance at Z = 3 is indicated with filled diamonds, and the line shows the corresponding standard error of the D-statistic. Plot colors indicate different pairs of geographic regions within Europe (blue: Europe S/Europe N; green: Europe S/Europe S).
Figure 3.
Results of TreeMix analysis of the Iceman with 1000G/Sardinia.
Shown are maximum-likelihood trees and the matrices of pairwise residuals (inset) for a model allowing (A) m = 0 and (B) m = 3 mixture events. Large positive values in the residual matrix indicate a poor fit for the respective pair of populations. Edges representing mixture events are colored according to weight of the inferred edge.
Figure 4.
A simplified model for recent demographic history of Europeans.
The panels indicate a possible demographic scenario consistent with the observed signals. (A) Mesolithic HGs present in mainland Europe prior to the arrival of agriculture. (B) Initial spread of farming from the Middle East beginning from 7,000 YBP into SE Europe. (C) Expansion of farming to N Europe from SE European gene pool and establishment of main S-N gradient of genetic diversity. Wave of migration also reaches Sardinia. (D) Continuous population expansion and admixture with local HGs as well as additional migrations continues to shape genetic diversity in mainland Europe, but Sardinia remains mostly isolated (IBD: isolation by distance).