Fluorescence in situ hybridization (FISH) using CTT microsatellite repetitive DNA probe was applied to produce CTT-banded karyotype of Aegilops species. CTT repeat identified individual chromosomes in all the studies species including diploids Ae. comosa (2n = MM), Ae. umbellulata (2n = UU) and allotetraploids Ae. biuncialis (2n = UbUbMbMb), Ae. geniculata (2n = UgUgMgMg), Ae. columnaris (2n = UcUcXcXc), Ae. neglecta (2n = UnUnXnXn) and Ae. crassa (2n = DcrDcrMcrMcr). FISH using CTT repeat produced banding patterns comparable with those of C-banding and proved to be a suitable alternative for chromosome identification and karyotypic analysis in the genus Aegilops. Intra specific chromosomal polymorphism and chromosomal arrangement were observed among different genotypes of each species. Based on banding patterns and arm ratios, X subgenomes of Ae. columnaris and Ae. neglecta resembled each other implying their origination from a common ancestor. However, they were distinct from and more heterochromatic compared to the M subgenome of Ae. biuncialis and Ae. geniculate. This finding is against the hypothesis that X subgenome may originated from Ae. comosa M genome. Although chromosomal CTT loci is generally absent on Ae. taushii chromosomes (DD genome), in Ae. crassa (DcrDcrMcrMcr genome) all chromosome pairs showed distinct CTT banding patterns indicating genomic arrangement and microsatellite repeat distribution between M and D subgenome in this species.
