Phylogeny, WGD, and gene families of Tibetan hulless barley compared with other plant genomes. (A) The divergence time tree estimated on fourfold degenerate sites of single-copy orthologous genes. (B) WGD and divergence of Tibetan hulless barley indicated by 4DTv (deviation at the fourfold degenerate third codon position) distribution. (C) Chromosomal syntenic relationship between Tibetan hulless barley and wheat A- and D-genome progenitors. (D) Gene families of H. vulgare, T. urartu, T. aestivum, Ae.tauschii, and B. distachyon. (E) Gene families of Ehrhardtoideae, Bambusoideae, Pooideae, and Panicoideae.