This study analysed cytogenetic events occurring in the syncytial endosperm of the Avena magna H. C. Murphy & Terrell × Avena longiglumis Durieu amphiploid, which is a product of two wild species having different genomes. Selection through the elimination of chromosomes and their fragments, including those translocated, decreased the level of ploidy in the endosperm below the expected 3n, leading to the modal number close to 2n. During intergenomic translocations, fragments of the heterochromatin-rich C-genome were transferred to the D and Al genomes. Terminal and non-reciprocal exchanges dominated, whereas other types of translocations, including microexchanges, were less common. Using two probes and by counterstaining with DAPI, the A. longiglumis and the rare exchanges between the D and Al genomes were detected by GISH. The large discontinuity in the probe labelling in the C chromosomes demonstrated inequality in the distribution of repetitive sequences along the chromosome and probable intragenomic rearrangements. In the nucleus, the spatial arrangement of genomes was non-random and showed a sectorial-concentric pattern, which can vary during the cell cycle, especially in the less stable tissue like the hybrid endosperm.

本研究分析了Avena magna HC Murphy & Terrell ×  Avena longiglumis Durieu 双倍体的合胞胚乳中发生的细胞遗传学事件，这是两个具有不同基因组的野生物种的产物。通过消除染色体及其片段（包括易位的那些）进行选择，将胚乳中的倍性水平降低到低于预期的 3 n，导致模态数接近 2 n. 在基因组间易位期间，富含异染色质的 C 基因组的片段被转移到 D 和 Al 基因组中。终端和非互惠交换占主导地位，而其他类型的易位，包括微交换，则不太常见。使用两个探针并通过 DAPI 复染，通过 GISH 检测到A. longiglumis以及 D 和 Al 基因组之间的罕见交换。C染色体中探针标记的大不连续性表明沿染色体的重复序列分布不均和可能的基因组内重排。在细胞核中，基因组的空间排列是非随机的，呈扇形同心圆模式，在细胞周期中会发生变化，尤其是在杂交胚乳等不太稳定的组织中。