Knob-associated tandem repeats, 180-bp repeats and TR-1 elements, together with 45S rDNA were located on mitotic chromosomes of Zea diploperennis (DP),maize inbred line F102 and their hybrid. In DP, knobs on the short...Knob-associated tandem repeats, 180-bp repeats and TR-1 elements, together with 45S rDNA were located on mitotic chromosomes of Zea diploperennis (DP),maize inbred line F102 and their hybrid. In DP, knobs on the short arm of chromosomes 1 and 4 and on the long arm ofthe chromosomes 4 and 5 are composed predominantly of the 180-bp repeats. In addition, 180-bp repeats existed together with TR-1 elements were also detected on the short arm ofchromosomes 2 and 5 and on the long arm of the chromosomes 2, 6, 7, 8 and 9. In maize inbred line F102, 180-bp repeats were present in chromosomes 7S and one homologue of chromosomes 8L. TR-1 elements appeared on satellite of chromosome 6 and no detectable hybridization site co-located with 180-bp repeats was observed in maize F102.Polymorphism of size, number, and distribution of 180-bp and TR-1 signals were revealed among different chromosomes in these two species and heteromorphism existed between some homologous chromosomes in the same species.Using these excellent landmarks, the interspecific hybrid of maize and DP were identified. The results suggest that comparative analysis of 180-bp repeats and TR-1 elements may help understand the genome organization and the evolution in Zea.展开更多
Knobs are blocks of heterochromatin present on chromosomes of maize （Zea mays L.） and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior. Knob heterozygosity...Knobs are blocks of heterochromatin present on chromosomes of maize （Zea mays L.） and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior. Knob heterozygosity and instability in six maize inbred lines and one Z. diploperennis Iltis Doebley line were investigated using the fluorescence in situ hybridization （FISH） technique with knob-associated tandem repeats （180 bp and 350 bp （TR- 1）） as probes. Signals of seven heterozygous knobs containing 180- bp repeats and of one heterozygous knob containing TR- 1 were captured in chromosomes of all materials tested according to the results of FISH, which demonstrates that the 180-bp repeat is the main contributor to knob heterozygosity compared with the TR- 1 element. In addition, one target cell with two TR- 1 signals on one homolog of chromosome 2L, which was different from the normal cells in the maize inbred line GB57, was observed, suggesting knob duplication and an instability phenomenon in the maize genome.展开更多
文摘Knob-associated tandem repeats, 180-bp repeats and TR-1 elements, together with 45S rDNA were located on mitotic chromosomes of Zea diploperennis (DP),maize inbred line F102 and their hybrid. In DP, knobs on the short arm of chromosomes 1 and 4 and on the long arm ofthe chromosomes 4 and 5 are composed predominantly of the 180-bp repeats. In addition, 180-bp repeats existed together with TR-1 elements were also detected on the short arm ofchromosomes 2 and 5 and on the long arm of the chromosomes 2, 6, 7, 8 and 9. In maize inbred line F102, 180-bp repeats were present in chromosomes 7S and one homologue of chromosomes 8L. TR-1 elements appeared on satellite of chromosome 6 and no detectable hybridization site co-located with 180-bp repeats was observed in maize F102.Polymorphism of size, number, and distribution of 180-bp and TR-1 signals were revealed among different chromosomes in these two species and heteromorphism existed between some homologous chromosomes in the same species.Using these excellent landmarks, the interspecific hybrid of maize and DP were identified. The results suggest that comparative analysis of 180-bp repeats and TR-1 elements may help understand the genome organization and the evolution in Zea.
文摘Knobs are blocks of heterochromatin present on chromosomes of maize （Zea mays L.） and its relatives that have effects on the frequency of genetic recombination, as well as on chromosome behavior. Knob heterozygosity and instability in six maize inbred lines and one Z. diploperennis Iltis Doebley line were investigated using the fluorescence in situ hybridization （FISH） technique with knob-associated tandem repeats （180 bp and 350 bp （TR- 1）） as probes. Signals of seven heterozygous knobs containing 180- bp repeats and of one heterozygous knob containing TR- 1 were captured in chromosomes of all materials tested according to the results of FISH, which demonstrates that the 180-bp repeat is the main contributor to knob heterozygosity compared with the TR- 1 element. In addition, one target cell with two TR- 1 signals on one homolog of chromosome 2L, which was different from the normal cells in the maize inbred line GB57, was observed, suggesting knob duplication and an instability phenomenon in the maize genome.
