Comparative analysis of the M genome in Aegilops comosa and Ae. heldreichii by means of C-banding technique and in situ hybridization

C-banding technique and irt situ hybridization with four DNA clones were em ployed in studying two related species of the genus Aegilops L., section Co mopyrum: Ae. comosa Sibth. ct Sm. and Ae. heldreichii Holzm. ex Boise. (gen omes M and M-h, respectively). The species were similar in karyotype struct ure, patterns of C-banding and hybridization with pSc119 and pAs1, and dist ribution of major and minor nucleolus organizer regions (NORs). However, th e total heterochromatin content, morphology and C-banding patterns of sever al chromosomes, and the number of the 5S rRNA gene loci differed. Thus, Ae. comosa and Ae. heldreichii had well-differentiated (though similar) genome s and must be considered as separate species.