Supplementary Material for: Interspecific Hybrids of <i>Hordeum marinum </i>ssp. <i>marinum </i>×<i> H. bulbosum </i>Are Mitotically Stable and Reveal No Gross Alterations in Chromatin Properties

Interspecific hybrids between the related wild barley species Hordeum marinum and H. bulbosum were generated and tested regarding their chromosomal stability and chromatin properties. Unlike in H. vulgare × H. bulbosum hybrid embryos, there was no effect of temperature on uniparental chromosome elimination or retention during hybrid seed development and 7 chromosomes from each parent were detected according to genomic in situ hybridization analyses. The centromere-specific histone H3 gene (CENH3) of both parental genomes is active in hybrid plants. Indirect immunostaining of flow-sorted 2C nuclei indicated that no major reorganization of histone H3 methylation (K4, K9 and K27), H3K9 acetylation and histone H2A ubiquitination marks or location of active RNA polymerase II sites occurred after interspecific hybridization.