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GrainGenes Reference Report: PLC-13-1735

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Reference	PLC-13-1735
Title	Allopolyploidy-induced rapid genome evolution in the wheat (Aegilops-Triticum) group
Journal	Plant Cell
Year	2001
Volume	13
Pages	1735-1747
Author	Ozkan H Levy AA Feldman M
Abstract	To better understand genetic events that accompany allopolyploid formation, we studied the rate and time of elimination of eight DNA sequences in F1 hybrids and newly formed allopolyploids of Aegilops and Triticum. In total, 35 inter-specific and intergeneric F1 hybrids and 22 derived allopolyploids were analyzed and compared with their direct parental plants. The studied sequences exist in all the diploid species of the Triticeae but occur in only one genome, either in one homologous pair (chromosome-specific sequences [CSSs]) or in several pairs of the same genome (genome-specific sequences [GSSs]), in the polyploid wheats. It was found that rapid elimination of CSSs and GSSs is a general phenomenon in newly synthesized allopolyploids. Elimination of GSSs was already initiated in F1 plants and was completed in the second or third allopolyploid generation, whereas elimination of CSSs started in the first allopolyploid generation and was completed in the second or third generation. Sequence elimination started earlier in allopolyploids whose genome constitution was analogous to natural polyploids compared with allopolyploids that do not occur in nature. Elimination is a nonrandom and reproducible event whose direction was determined by the genomic combination of the hybrid or the allopolyploid. It was not affected by the genotype of the parental plants, by their cytoplasm, or by the ploidy level, and it did not result from intergenomic recombination. Allopolyploidy-induced sequence elimination occurred in a sizable fraction of the genome and in sequences that were apparently noncoding. This finding suggests a role in augmenting the differentiation of homoeologous chromosomes at the polyploid level, thereby providing the physical basis for the diploid-like meiotic behavior of newly formed allopolyploids. In our view, this rapid genome adjustment may have contributed to the successful establishment of newly formed allopolyploids as new species
External Databases	Pubmed: 11487689
Keyword	[ Hide all but 1 of 37 ] aegilops allopolyploid angiosperms behavior chromosome chromosome arm common wheat cotton cytoplasm differentiation dna dna sequence elimination establishment events evolution fraction generation genome genome evolution genotype homoeologous chromosomes hybrid hybridization meiotic behavior new species newly synthesized amphiploids ploidy polyploid polyploid wheat polyploidy rate recombination sequence speciation triticeae triticum

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