Characterisation of the low-chromosome number grass Colpodium versicolor (Stev.) Schmalh. (2n = 4) by molecular cytogenetics

Abstract

— Agenome size of 2C = 235 Mbp and the chromosomal positions of the 5S and 45S rDNA were determined for the perennial, low-chromosome grass Colpodium versicolor (2n = 4). Based on taxonomical and cytological data we suggested previously that C. versicolor represents a putative donor of one of the two parental genomes of the allotetraploid grass Zingeria trichopoda (2n = 8). To test this hypothesis sequence comparison of the ITS1-5.8S-ITS2 -region (part of the 18S rDNA) and genomic in situ hybridization were performed. Although the ITS1-5.8S-ITS2 sequences of C. versicolor and Z. trichopoda are highly similar, genomic in situ hybridization of Z. trichopoda with labeled genomic DNA of C. versicolor did not result in a subgenome-specific labeling of Z. trichopoda chromosomes. Thus, the contemporary species C. versicolor is a closely related but not the direct ancestor of the allopolyploid species Z. trichopoda.

Key words:

• dysploid reduction
• genome evolution
• low-chromosome number species
• Poaceae