title: The evolution of the hexaploid grass Zingeriakochii (Mez) Tzvel. (2n=12) was accompanied by complex hybridization and uniparental loss of ribosomal DNA.
abstract: In the grass tribe Poeae a small group of taxa occur with an exceptionally low chromosome number of 2n=2x=4 belonging to the closely related genera Colpodium and Zingeria. To understand the formation of polyploids in this group we analyzed the evolution of allohexaploid Zingeriakochii (2n=12) and its presumable ancestral species. Genomic insitu hybridization demonstrated that Z.kochii evolved from an interspecific hybrid involving species closely related to contemporary Z.biebersteiniana (2n=4) and Colpodiumversicolor (2n=4) and a third unknown species. Following allopolyploidization of Z.kochii the biebersteiniana-like parental chromosomes underwent loss of ribosomal DNA. No interlocus homogenization of 45S rDNA took place in Z.kochii and phylogenetic analysis showed that C.versicolor contributed its genome to Z.kochii relatively recently. Insitu hybridization was particularly effective in understanding the allopolyploid evolution in Zingeria while the analysis of ITS sequences alone would have resulted in a wrong interpretation of the allopolyploid history of the genus.
authors.affiliation: Komarov Botanical Institute, St. Petersburg, Russia.
authors.forename: Violetta
authors.initials: V
authors.lastname: Kotseruba
authors.forename: Klaus
authors.initials: K
authors.lastname: Pistrick
authors.forename: Frank R
authors.initials: FR
authors.lastname: Blattner
authors.forename: Katrin
authors.initials: K
authors.lastname: Kumke
authors.forename: Oda
authors.initials: O
authors.lastname: Weiss
authors.forename: Twan
authors.initials: T
authors.lastname: Rutten
authors.forename: Jörg
authors.initials: J
authors.lastname: Fuchs
authors.forename: Takashi
authors.initials: T
authors.lastname: Endo
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nasuda
authors.forename: Anahit
authors.initials: A
authors.lastname: Ghukasyan
authors.forename: Andreas
authors.initials: A
authors.lastname: Houben
mesh_terms: D032461:Chromosomes, Plant; D018744:DNA, Plant / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D019143:Evolution, Molecular; D018745:Genome, Plant; D017404:In Situ Hybridization, Fluorescence; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D006109:Poaceae / Q000145:classification / Q000235:genetics*; D011123:Polyploidy; D012335:RNA, Ribosomal / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal; D012335:RNA, Ribosomal; C088179:RNA, ribosomal, 45S