The barley Genome and its Relationship with the Wheat Genomes. A Survey with an Internationally Agreed Recommendation for Barley Chromosome Nomenclature

Abstract

The paper reviews recent literature on the cytology, cytogenetics, molecular cytogenetics, and gene structure of barley, and on the relationship of the barley and wheat genomes. The information collected demonstrates largely similar genetic contents and collinearity of gene loci in the seven chromosomes of barley and in those of other members of the Triticeae. The high level of synteny indicates that the whole group can be considered as a single gene pool. On this basis, the 7th International Barley Genetics Symposium recommended that (i) the currently used designations of the barley chromosomes (the BURNHAM and HAGBERG system) should become secondary to the use of the Triticeae system; i.e., each of the seven barley chromosomes is designated by a numeral between 1 and 7 according to its homoeologous relationship with the chromosomes of the wheat genomes followed by the genomic symbol H, e.g., 2H; (ii) the genomes of Hordeum vulgare and H. bulbosum are symbolized with the letter H; and (iii) the arms of the barley chromosomes are designated by the capital letters S and L (cf. SINGHand TSUCHIYA 1982b). Further, it was recommended that the barley genome present in the barley cultivar ‘Betzes’ should become the reference genome in the Triticeae.

Extensive chromosomal variation in a recently formed natural allopolyploid species,Tragopogon miscellus(Asteraceae)

“…This inference of homeology in T. miscellus is underscored for chromosome groups B-E, which were found in nulli-tetrasomic combinations in T. miscellus. In other allopolyploids, substantial synteny is required for compensation of complete chromosome loss (nullisomy) by chromosomes from another progenitor or related species (23,32,(38)(39)(40). The data that we report suggest that chromosomes A-F of T. dubius and T. pratensis origin correspond to six groups of largely homologous (homeologous) chromosomes.…”

Wheat–barley hybridization: the last 40 years

“…The translocation chromosome was identified with C-banding and, using an earlier nomenclature, it was found that it involved the short arm of chromosome 7 of barley and the long arm of wheat chromosome 5B. When the names of the barley chromosomes were later revised, the old chromosome 7 was renamed 5H (Linde-Laursen et al 1997) and it became clear that a homoeologous translocation had indeed taken place.…”

Transcriptional Activity of Translocated NORs in Barley (Hordeum VulgareL.)

“…in standard barley karyotype the size of the primary nucleoli varied pairwise indicating that both chromosome pairs differed in their nucleolus forming capacity (2,28,41). As tsuchiya (56) and Anastassova-Kristeva et al (2) mentioned, the noR6h is functionally stronger (shows a wider secondary constriction) and produces a larger nucleolus than chromosome 5h although noR 5h contains 70% more rDnA than noR 6h (54,55).…”