The bread wheat genome harbors a high content of repetitive DNA,which is amenable to detection and characterization using fluorescence in situ hybridization(FISH)karyotyping.An integrated genetic map was derived from ...The bread wheat genome harbors a high content of repetitive DNA,which is amenable to detection and characterization using fluorescence in situ hybridization(FISH)karyotyping.An integrated genetic map was derived from a recombinant inbred population bred from a cross between a synthetic hexaploid wheat and a commercial Chinese bread wheat cultivar,based on 28 variable FISH sites and>150000 single nucleotide polymorphism(SNP)loci.The majority(20/28)of the variable FISH sites were physically located within a chromosomal region consistent with the genetic location inferred from that of their co-segregating SNP loci.The eight exceptions reflected the presence of either a translocation(1 R/1 B,1 A/7 A)or a presumptive intra-chromosomal inversion(4 A).For eight out of the nine FISH sites detected on the Chinese Spring(CS)karyotype,there was a good match with the reference genome sequence,indicating that the most recent assembly has dealt well with the problem of placing tandem repeats.The integrated genetic map produced for wheat is informative as to the location of blocks of tandemly repeated DNA and can aid in improving the quality of the genome sequence assembly in regions surrounding these blocks.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
基金financially supported by the National Key Research and Development Program of China(2016YFD0102000)。
文摘The bread wheat genome harbors a high content of repetitive DNA,which is amenable to detection and characterization using fluorescence in situ hybridization(FISH)karyotyping.An integrated genetic map was derived from a recombinant inbred population bred from a cross between a synthetic hexaploid wheat and a commercial Chinese bread wheat cultivar,based on 28 variable FISH sites and>150000 single nucleotide polymorphism(SNP)loci.The majority(20/28)of the variable FISH sites were physically located within a chromosomal region consistent with the genetic location inferred from that of their co-segregating SNP loci.The eight exceptions reflected the presence of either a translocation(1 R/1 B,1 A/7 A)or a presumptive intra-chromosomal inversion(4 A).For eight out of the nine FISH sites detected on the Chinese Spring(CS)karyotype,there was a good match with the reference genome sequence,indicating that the most recent assembly has dealt well with the problem of placing tandem repeats.The integrated genetic map produced for wheat is informative as to the location of blocks of tandemly repeated DNA and can aid in improving the quality of the genome sequence assembly in regions surrounding these blocks.
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.
