ISSN:
1432-2242
Keywords:
Key words Wheat
;
Aegilops comosa
;
Translocation
;
Homoeologous recombination
;
RFLP
;
C-banding
;
Genomic in situ hybridization
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The genetic constitutions of chromosome 2M of Aegilops comosa and the derived wheat-Ae. comosa translocations were analyzed by molecular cytogenetic techniques. Hybridization of 15 RFLP markers covering the entire length of the group-2 chromosomes revealed that chromosome 2M was structurally rearranged compared to the homoeologous chromosomes of wheat by either a pericentric inversion or a terminal intrachromosomal translocation. The breakpoint of the rearrangement was located in a region between the loci Xpsr131 and Xcdo405, resulting in the translocation of 47% of 2MS to 2ML. This aberrant structure of 2M allowed homoeologous recombination between 2M and its wheat counterpart only in the translocated segment on 2ML. C-banding and genomic in situ hybridization analyses confirmed that all translocation chromosomes consisted of the complete 2MS arm, a large part of 2ML, and very small distal segments derived from 2AS or 2DS, as expected from the aberrant structure of chromosome 2M. Thus, the translocation in the line 2A-2M?4/2 can be described as T2AS-2M?1L ⋅ 2M?1S and the translocations in the lines Compair and 2D-2M?3/8 as T2DS-2M?1L ⋅ 2M?1S. RFLP analysis determined the breakpoints in these translocation chromosomes to be within the telomeric 16% of the wheat chromosome arms. The breakpoint of the 2A/2M translocation was between Xbcd348 and Xcdo783, and that of the 2D/2M translocation was between Xcdo783 and Xpsr666. Because the translocation chromosomes retain the structural aberration found in chromosome 2M, further exploitation of the wheat-Ae. comosa translocations for cultivar improvement is questionable.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001220050802
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