Excavating Neandertal and Denisovan DNA from the genomes of Melanesian individuals

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Science  17 Mar 2016:
DOI: 10.1126/science.aad9416
  • Fig. 1 Melanesian genomic variation in a global context.

    (A) Locations of the 159 geographically diverse populations studied. Information on the Melanesian individuals sequenced (blue triangles) is shown in the inset. (B) PCA of Melanesian genomes in the context of present-day worldwide genetic diversity. (C) Modern human variation projected onto the top two eigenvectors defined by PCA of the Altai Neandertal, Denisova, and chimpanzee genome (14). Population means were plotted for each of the 11 Melanesian populations and each population of the global dataset. (D) Estimates of Denisova ancestry in Oceanic populations estimated from an f4 statistic (14). The 11 Melanesian populations are highlighted by the light blue box.

  • Fig. 2 Identifying Neandertal and Denisovan sequences in modern human genomes.

    (A) Bivariate archaic match P value distributions for simulations of non-introgressed sequence, Esan in Nigeria, Europeans, and Melanesians. Null simulations and Esan show no skew in Neandertal or Denisovan match P values toward zero, Europeans show only a skew of Neandertal match P values toward zero, and Melanesians exhibit both Neandertal and Denisovan match P values skewed toward zero. (B) Amount of archaic introgressed sequence identified in each population. Inset, amount of Neandertal, Denisovan, and ambiguous (Neandertal or Denisovan) introgressed sequence for each Melanesian individual. (C) Schematic representation of introgressed haplotypes in an intronic portion of the GRM7 locus in Melanesian individuals illustrating mosaic patterns of archaic ancestry.

  • Fig. 3 Identifying shared and unique pulses of Neandertal admixture among human populations.

    (A) Schematics of two simulated introgression models, and patterns of reciprocal match probabilities. Contour plots are fit to the scatterplot of reciprocal match probabilities calculated from analyzing all pairwise combinations of individuals between two populations. Left, gene flow occurs into the common ancestor of Population 1 and Population 2, and reciprocal match probabilities fall along the diagonal as predicted by theory (Binomial test, P > 0.05) (14). Right, Population 2 receives additional admixture shifting reciprocal match probabilities above the diagonal (Binomial test, P < 0.05). (B) Reciprocal match probabilities of Neandertal sequences in modern human populations, consistent with additional Neandertal admixture into East Asians versus Europeans, and into Europeans, East Asians and South Asians versus Melanesians. (C) Schematic of admixture history consistent with the data.

  • Fig. 4 Maps of archaic admixture reveal signatures of purifying and positive selection.

    (A) Proportion of windows significantly depleted of Neandertal introgression in Europeans and East Asians (dashed line) versus what is expected in neutral demographic models (95% CI in gray). (B) Distribution of Neandertal and Denisovan sequence across chromosome 7 in Melanesians (MEL), East Asians (EAS), South Asians (SAS), Europeans (EUR), and summed across all populations (TOT). Masked regions are shown as grey vertical lines. An 11.1 Mb region significantly depleted of Denisovan and Neandertal ancestry in all populations is shown in light gray. (C) The frequency of archaic haplotypes in Melanesians versus Europeans. The red line indicates the 99th percentile defined by neutral coalescent simulations. Notable genes are labeled. (D) Visual representation of a high frequency haplotype encompassing GBP4 and GBP7. Rows indicate individual haplotypes and columns denote variants that tag the introgressed haplotype (14). Alleles are colored according to whether they are ancestral (white), derived variants that match both archaic genomes (blue), derived variants that match one archaic genome (dark grey), or are derived but do not match either archaic genome (light gray). Archaic sequences are represented above, with black denoting derived variants. Missense, UTR, and putative regulatory variants (14), are highlighted with red boxes.

Supplementary Materials

  • Excavating Neandertal and Denisovan DNA from the genomes of Melanesian individuals

    Benjamin Vernot, Serena Tucci, Janet Kelso, Joshua G. Schraiber, Aaron B. Wolf, Rachel M. Gittelman, Michael Dannemann, Steffi Grote, Rajiv C. McCoy, Heather Norton, Laura B. Scheinfeldt, David A. Merriwether, George Koki, Jonathan S. Friedlaender, Jon Wakefield, Svante Pääbo, Joshua M. Akey

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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    • Materials and Methods
    • Figs. S1 to S22
    • Tables S1 to S12
    • References

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