Elimination and rearrangement of parental rDNA in the allotetraploid Nicotiana tabacum

Origin and rearrangement of ribosomal DNA repeats in natural allotetraploid Nicotiana tabacum are described. Comparative sequence analysis of the intergenic spacer (IGS) regions of Nicotiana tomentosiformis (the paternal diploid progenitor) and Nicotiana sylvestris (the maternal diploid progenitor)...

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Bibliographic Details
Published in:Molecular biology and evolution 1999-03, Vol.16 (3), p.311-320
Main Authors: Volkov, R A, Borisjuk, N V, Panchuk, I I, Schweizer, D, Hemleben, V
Format: Article
Language:English
Subjects:
Base Sequence
DNA, Plant - genetics
DNA, Ribosomal - genetics
Evolution, Molecular
Gene Rearrangement
Genome, Plant
Molecular Sequence Data
Nicotiana - genetics
Nicotiana sylvestris
Nicotiana tabacum
Nicotiana tomentosiformis
Plants, Toxic
Polymorphism, Genetic
Polyploidy
Repetitive Sequences, Nucleic Acid
Restriction Mapping
Sequence Homology, Nucleic Acid
Species Specificity
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Summary:Origin and rearrangement of ribosomal DNA repeats in natural allotetraploid Nicotiana tabacum are described. Comparative sequence analysis of the intergenic spacer (IGS) regions of Nicotiana tomentosiformis (the paternal diploid progenitor) and Nicotiana sylvestris (the maternal diploid progenitor) showed species-specific molecular features. These markers allowed us to trace the molecular evolution of parental rDNA in the allopolyploid genome of N. tabacum; at least the majority of tobacco rDNA repeats originated from N. tomentosiformis, which endured reconstruction of subrepeated regions in the IGS. We infer that after hybridization of the parental diploid species, rDNA with a longer IGS, donated by N. tomentosiformis, dominated over the rDNA with a shorter IGS from N. sylvestris; the latter was then eliminated from the allopolyploid genome. Thus, repeated sequences in allopolyploid genomes are targets for molecular rearrangement, demonstrating the dynamic nature of allopolyploid genomes.
ISSN:0737-4038
1537-1719
DOI:10.1093/oxfordjournals.molbev.a026112