Heterozygosity of Knob-Associated Tandem Repeats and Knob Instability in Mitotic Chromosomes of Zea （Zea mays L. and Z. diploperennis Iltis Doebley）  

作　　者：Zhi-Yong XIONG Yong LIU Yong-Gang HE Yun-Chun SONG Ke-Xiu LI Guan-Yuan HE 

机构地区：[1]China-UK HUST-RRes （Rothamsted Reseach, UK） Genetic Engineering and Genomics Joint Laboratory, Huazhong University of Science and Technology （HUST）, Wuhan 430074, China [2]Key Laboratory of the Ministry of Education for Plant Developmental Biology, Wuhan University, Wuhan 430072, China

出　　处：《Journal of Integrative Plant Biology》2005年第11期1345-1351,共7页植物学报（英文版）

基　　金：国家自然科学基金，国家高技术研究发展计划(863计划)，国家重点基础研究发展计划(973计划)

摘　　要：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.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.

关 键 词：fluorescence in situ hybridization KNOB repetitive DNA sequence Zea diploperennis Z. mays. 

分 类 号：Q969.41[生物学—昆虫学]