Physical mapping of the 45S rDNA on the chromosomes of Triticum turgidum and T. aestivum using fluorescence in situ hybridization for chromosome ancestors [electronic resource].

Includes references.

Four amphiploid varieties of wheat in Egypt belonging to two species (Triticum turgidum and T. aestivum) were analyzed by fluorescence in situ hybridization (FISH) using 18S, 5.8S and 26S ribosomal genes (45S rDNA), which were applied to mitotic chromosome spreads. Tetra-amphiploids of Bani Suief (AABB genome; 2n=28) showed four subterminal FISH yellow signals and the hexa-amphiploids of Sids (AABBDD genome; 2n=42) showed six signals of which four were subterminal as those of the tetraploid (AABB) and two signals were terminal that might be related to the D genome. This rDNA mapping was also able to reveal differences in the genome composition that were mainly in the NOR. The FISH signals of the 45S rDNA sites of metaphase chromosomes were confirmed at interphase of all varieties studied. FISH signals were 12 sites of the 45S rDNA in each chromosome complements of the polyploidy species of Chrysanthemum indicum (tetraploid; 2n=36), Ch. occidentali-japonense (hexaploids; 2n=54) and Ch. vestitum (hexaploids; 2n=54). The ratio of FISH signal numbers per chromosome complement were decreasing with increasing the chromosome numbers in Chrysanthemum species, while they were stable in wheat varieties

Summary in Arabic.

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