Fig. 1

A partial duplication of the E3 ligase gene PUB15 in Triticeae species gave rise to ARM1. a Schematic view of the genomic structure of HvPUB15 and its partial duplicate HvARM1. Red boxes and blue lines represent exon and intron sequences, respectively. The region of high sequence homology is indicated by light gray shading. b DNA sequence alignment around the U-box domain of PUB15. Note the absence of sequence alignment (gaps and different colors) in the 5′ end of the U-box in ARM1. c DNA sequence alignment around the translational start of ARM1. The two proposed translation start sites of ARM1 are inside the red frames, and the initial frame of PUB15 is restored by an 8-bp deletion (frameshift correction) downstream from the first 5 amino acids of ARM1 and is indicated by a brace. d Protein sequence alignment of PUB15 and ARM1 at the N-terminus of ARM1. e Phylogenetic tree of both proteins based on alignment of overlapping PUB15 and ARM1 coding sequences. A maximum likelihood tree with OsPUB15 as outgroup was calculated and bootstrap values (in percent) based on 100 reiterations are indicated along the branches and tree depth (in changes per nucleotide position) by scale bar. f Conservative selection at the armadillo-repeat domain of ARM1 among Triticeae species. The ratio of non-synonymous to synonymous nucleotide exchanges (ω) among PUB15 and ARM1 genes overlapping region of six Triticeae species plus rice was calculated. Posterior mean ω + standard error (SE) are reported over 40 non-ambiguous amino acid positions sliding window, with a step size of 20. a–f Species binomial abbreviations: Aes, Aegilops speltoides, Aet, Aegilops tauschii (wild wheat close relatives); Hv, Hordeum vulgare (barley); Os, Oryza sativa (rice); Sc, Secale cereale (rye), Ta, Triticum aestivum (wheat) followed by homeolog orgin, Tu, Triticum urartu (wild wheat close relative). b–d Disagreements to majority consensus are highlighted in color. Accession numbers of publicly available sequences are listed in Additional file 1: Table S10