MAHELKA, Václav, KOPECKÝ, David, MAJKA, Joanna, KRAK, Karol. Uniparental expression of ribosomal RNA in ×Festulolium grasses: a link between the genome and nucleolar dominance. Frontiers in Plant Science. 2023, 14(18 September), 1276252. ISSN 1664-462X. E-ISSN 1664-462X

In hybrids resulting from interspecific crosses, there are usually competitive processes between individual subgenomes that result in some form of genomic dominance. However, this manifests itself in different ways and it is not clear that the dominant genome is always the same. In hybrids between fescues (Festuca) and ryegrasses (Lolium) that exhibit genomic dominance at the whole-genome level, we have studied nucleolar dominance (which manifests at the ribosomal DNA level) to determine whether the dominant genome is identical. In 31 genotypes from 4 generations and five hybrid combinations, we found that the dominant genome for nucleolar dominance was always identical to the dominant genome at the genome-wide level. Therefore, it is likely that genome-wide and nucleolar dominance are not independent processes.