Contrasting patterns of evolution of 45S and 5S rDNA families uncover new aspects in the genome constitution of the agronomically important grass Thinopyrum intermedium (Triticeae)

0395682 - BÚ 2014 RIV US eng J - Journal Article
Mahelka, Václav - Kopecký, David - Baum, B. R.
Contrasting patterns of evolution of 45S and 5S rDNA families uncover new aspects in the genome constitution of the agronomically important grass Thinopyrum intermedium (Triticeae).
Molecular Biology and Evolution. Roč. 30, č. 9 (2013), s. 2065-2086. ISSN 0737-4038. E-ISSN 1537-1719
R&D Projects: GA ČR GA13-04454S
Institutional support: RVO:67985939 ; RVO:61389030
Keywords : Triticeae * polyploidy * roibosomal DNA
Subject RIV: EF - Botanics; EF - Botanics (UEB-Q)
Impact factor: 14.308, year: 2013

Sequence variation and genomic organization of 45S and 5S rDNA families in the allohexaploid grass Thinopyrum intermedium showed that both families have undergone different patterns of evolution. ITS sequences residing within the arrays of two subgenomes out of three got homogenized towards one major ribotype, while the third subgenome contained a minor proportion of distinct unhomogenized copies. Homogenization mechanisms such as unequal crossover and/or gene conversion were coupled with the loss of certain 45S rDNA loci. Unlike in the 45S family, the data suggest that neither interlocus homogenization among homeologous chromosomes nor locus loss occurred in 5S rDNA. 5S sequences suggested the contributions from Aegilops to the intermediate wheatgrass’ genome, which is a new finding with implications in wheat improvement.
Permanent Link: http://hdl.handle.net/11104/0223631