Does time matter? Intraspecific diversity of ribosomal RNA genes in lineages of the allopolyploid model grass Brachypodium hybridum with different evolutionary ages
Background Polyploidisation often results in genome rearrangements that may involve changes in both the single-copy sequences and the repetitive genome fraction. In this study, we performed a comprehensive comparative analysis of repetitive DNA, with a particular focus on ribosomal DNA (rDNA), in Br...
| Authors: | , , , , , , , , , , , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2024 |
| Country: | España |
| Institution: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repository: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/370329 |
| Online Access: | http://hdl.handle.net/10261/370329 |
| Access Level: | Open access |
| Keyword: | rDNA loci Brachypodium hybridum 5S rDNA NTS nrITS 35S rDNA IGS FISH |
| Summary: | Background Polyploidisation often results in genome rearrangements that may involve changes in both the single-copy sequences and the repetitive genome fraction. In this study, we performed a comprehensive comparative analysis of repetitive DNA, with a particular focus on ribosomal DNA (rDNA), in Brachypodium hybridum (2n¿=¿4x¿=¿30, subgenome composition DDSS), an allotetraploid resulting from a natural cross between two diploid species that resemble the modern B. distachyon (2n¿=¿10; DD) and B. stacei (2n¿=¿20; SS). Taking advantage of the recurrent origin of B. hybridum, we investigated two genotypes, Bhyb26 and ABR113, differing markedly in their evolutionary age (1.4 and 0.14 Mya, respectively) and which resulted from opposite cross directions. To identify the origin of rDNA loci we employed cytogenetic and molecular methods (FISH, gCAPS and Southern hybridisation), phylogenetic and genomic approaches. Results Unlike the general maintenance of doubled gene dosage in B. hybridum, the rRNA genes showed a r |
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