Fig. 5: Divergence and dispersal of domesticated barley.

a, Violin plots showing the distribution of sequence divergence (SNPs per Mb) in pairwise comparisons between samples from different populations of domesticated barley. The dashed lines mark the peaks of the distributions (split times). Multimodal distributions may have risen from episodes of gene flow. b, Schematic illustrating the lineal descent and split times between 15 barley populations defined in this study and Tibetan barleys (Qingke) studied by Zeng et al.⁴⁰. c, Map showing when and along which routes domesticated barley spread from its centre of origin in the Fertile Crescent. The grey shading indicates barley archaeological sites dating back about 7,000 years; the red shading indicates barley archaeological sites dating back about 5,000 years²⁷. We took archaeological sites²⁷, divergence time and population structure (Supplementary Fig. 8) into account when drawing this figure. Geographical outlines were obtained from the R package ‘maps’ (https://CRAN.R-project.org/package=maps), which uses public domain base map data (under a GNU General public license: version 2). d, D statistics for different comparisons among ancient barleys and 15 domesticated barley populations. The outgroup was H. pubiflorum. Blue and red indicate significant results (|Z score| > 3), whereas grey indicates non-significant results (|Z score| < 3). A positive D value (blue) suggests gene flow between P1 and P3, whereas a negative D value (red) indicates gene flow between P2 and P3. The grey bars, with D values close to zero, imply no detectable gene flow. The solid circles represent D values. The error bars indicate ±1 standard error. Sample sizes of each population, standard deviations and Z values are provided in Supplementary Table 19.