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GrainGenes Reference Report: GNM-43-923

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Reference	GNM-43-923
Title	Chromosome structure of Triticum timopheevii relative to T-turgidum
Journal	Genome
Year	2000
Volume	43
Pages	923-930
Author	Rodriguez S Perera E Maestra B Diez M Naranjo T
Abstract	Summary: The chromosome structure of four different wild populations and a cultivated line of Triticum timopheevii (2n = 28, A(t)A(t)GG) relative to Triticum turgidum (2n = 28, AABB) was studied, using genomic in situ hybridisation (GISH) and C-banding analysis of meiotic configurations in interspecific hybrids. Two wild accessions and the cultivated line showed the standard C-banding karyotype. The other two accessions are homozygous for translocation 5A(t)/3G and translocations 1G/2G and 5G/6G. GISH analysis revealed that all the T. timopheevii accessions carry intergenome translocations 6A(t)/1G and 1G/4G and identified the position of the breakpoint in translocation 5A(t)/3G. C-banding analysis of pairing at metaphase I in the hybrids with T. turgidum provides evidence that four species-specific translocations (6A(t)S/1GS, 1GS/4GS, 4GS/4A(t)L, and 4A(t)L/3A(t)L) exist in T. timopheevii, and that T. timopheevii and T. turgidum differ in the pericentric inversion of chromosome 4A. Bridge plus acentric fragment configurations involving 4AL and 4A(t)L were identified in cells at anaphase I. This result suggests that the paracentric inversion of 4AL from T. turgidum does not exist in T. timopheevii. Both tetraploid species have undergone independent and distinct evolutionary chromosomal rearrangements. The position, intercalary or subdistal, of the breakpoints in species-specific translocations and inversions contrasts with the position, at or close to the centromere, of intraspecific translocations. Different mechanisms for intraspecific and species-specific chromosome rearrangements are suggested
Keyword	[ Hide all but 1 of 33 ] accessions aegilops araraticum poaceae c banding canada cell centromere chloroplast dna chromosome pairing differentiation evolution gish hybrid in situ interspecific hybrids inversion karyotype mechanism metaphase nuclear dna pericentric inversion phylogeny polyploid wheats population rearrangements rflp analysis rye timopheevii translocation triticum timopheevii triticum turgidum turgidum wild

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