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GrainGenes Reference Report: TAG-99-1087

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Reference	TAG-99-1087
Title	Variable genome composition in TriticumxLeymus amphiploids
Journal	Theoretical and Applied Genetics
Year	1999
Volume	99
Pages	1087-1093
Author	Anamthawat-Jonsson K
Abstract	Summary: Three different amphiploid lines originated from crosses between wheat (Triticum L.) and lymegrass (Leymus Hochst.) were analysed by fluorescence in situ hybridization (FISH) using total genomic DNA and 18S.26S ribosomal genes (rDNA). Based on the genomic probes, these lines were the same in that they all were allohexaploids (2n=6x=42) containing 30 wheat and 12 lymegrass chromosomes. The ribosomal gene mapping further identified species origin of the chromosomes, whereby the lymegrass parent was undoubtedly L. mollis and the wheat was likely to be a Triticum species having the AB genomes. This rDNA mapping was also able to reveal differences in the genome composition among these lines, and such differences were mainly in the wheat nucleolar organizing regions (Nor). The first line (M) had two Nor-B1 (1BS), the second line (G) had one Nor-B1 (1BS), two Nor-B2 (6BS) and two Nor-A1 (1AS), whereas the third line (U) had the same Nor loci as the second line but two sites each. The wheat ribosomal genes were variably expressed depending on the lines, but the lymegrass loci appeared inactive. All three lines had the same Nor loci belonging to L. mollis, two Nor-m1 and two Nor-m2. Analysis of restriction fragment length polymorphism (RFLP) of the rDNA confirmed the identity of L. mollis parent in all three lines and verified the differences in the wheat ribosomal genes among them. These amphiploids were, however, similar in their restriction profiles, therefore indicating common origin. The molecular and cytogenetic evidence here suggested that these annual, fully fertile amphiploids that originated from the same crosses 40 years ago became genetically differentiated and fixed in stable forms
External Databases	http://link.springer.de/link/service/journals/00122/bibs/9099007/90991087.htm
Keyword	[ Hide all but 1 of 40 ] amphiploid amphiploids chromosome maps dna dna hybridization dna probes fertile fish fluorescence fluorescence in situ hybridization fragment length polymorphism gene gene mapping genetic mapping genome genome analysis genomic dna hexaploidy hybridization in situ in situ hybridization intergeneric hybridization leymus leymus arenarius loci mapping molecular mapping nor nucleolus organizer origin polymorphism probes rdna rflp ribosomal dna ribosomal genes triticum triticum aestivum triticum durum wide hybridization

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