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GrainGenes Reference Report: GNM-42-1013

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Reference
GNM-42-1013
Title
Physical mapping of wheat-Aegilops longissima breakpoints in mildew-resistant recombinant lines using FISH with highly repeated and low-copy DNA probes
Journal
Genome
Year
1999
Volume
42
Pages
1013-1019
Author
Biagetti M
Vitellozzi F
Ceoloni C
Abstract
Summary: Fluorescence in situ hybridization (FISH) with multiple probes, consisting of highly repeated DNA sequences (pSc119.2 and pAs1) and of a low-copy, 3BS-specific RFLP sequence (PSR907), enabled determination of the physical position of the wheat-alien breakpoints (BPs) along the 3BS and 3DS arms of common wheat recombinant lines. These lines harbour 3S(1)S Aegilops longissima segments containing the powdery mildew resistance gene Pm13. In all 3B recombinants, the wheat-Aegilops longissima physical BPs lie within the interval separating the two most distal of the three pSc119.2 3BS sites. In all such recombinants a telomeric segment, containing the most distal of the pSc119.2 3BS sites, was in fact replaced by a homoeologous Ae. longissima segment, marked by characteristic pSc119.2 hybridization sites. Employment of the PSR907 RFLP probe as a FISH marker allowed to resolve further the critical region in the various 3B recombinant lines. Three of them, like the control common wheat, exhibited between the two most distal pSc119.2 sites a single PSR907 FISH site, which was missing in a fourth recombinant line. The amount of alien chromatin can thus be estimated to represent around 20% of the recombinant arm in the three former lines and a maximum of 27% in the latter. A similar physical length was calculated for the alien segment contained in three 3D recombinants, all characterized by the presence of the Ae. longissima pSc119.2 sites distal to the nearly telomeric pAs1 sites of normal 3DS. Comparison between the FISH-based maps and previously developed RFLP maps of the 3BS-3S(1)S and 3DS-3S(1)S arms revealed substantial differences between physical and genetic map positions of the wheat-alien BPs and of molecular markers associated with the critical chromosomal portions
Gene
Sr9 (Triticum)
Keyword
[ Hide all but 1 of 23 ]
aegilops longissima
chromatin
common wheat
dna
dna hybridization
fish
gene
gene location
genetic mapping
genetic markers
hybridization
intergeneric hybridization
map
mapping
maps
molecular marker
powdery mildew resistance
recombination
resistance
rflp
rflp map
sequence
triticum aestivum

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