Robertsonian translocations in wheat arise by centric misdivision of univalents at anaphase I and rejoining of broken centromeres during interkinesis of meiosis II
Robertsonian translocations in wheat arise by centric misdivision of univalents at anaphase I and rejoining of broken centromeres during interkinesis of meiosis II
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DOI：
10.1159/000082412
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发表时间：
2005-01-01
影响因子：
1.7
通讯作者：
Gill, BS
中科院分区：
文献类型：
--
作者：
Friebe, B;Zhang, P;Gill, BS
通过GISH研究了小麦1A染色体和粗麦1H(t)单体植物中罗伯逊易位的起源机制。在分析的所有中期 I 细胞中，染色体 1A 和 1H(t) 保持单价，这表明罗伯逊易位并非源自具有共享 DNA 序列同源性的着丝粒区域的减数分裂重组。在后期/末期 I，1H(t) 和 1A 单价体经历染色体或染色单体分离，并在 6 - 7% 的花粉母细胞中错误分裂。我分析的后期/末期均没有罗伯逊易位，仅在后期/末期 II 的 2% 的“半四分体”中观察到这种易位。在后期/末期 II 观察到的罗伯逊易位频率与在小麦第 1 组染色体（1A、1B 和 1D）和 E. trachycaulus 1H(t) 单体染色体的植物后代中检测到的罗伯逊易位数量 (1 - 4%) 非常一致。我们的数据表明，罗伯逊易位源于单价体在后期/末期 I 的中心错误分裂，随后衍生的端着丝粒染色体分离到同一核，并在随后的相互运动过程中断裂末端的融合。版权所有 (C) 2005 S. Karger AG，巴塞尔。
The mechanism of origin of Robertsonian translocations was investigated in plants monosomic for chromosome 1A of wheat and 1H(t) of Elymus trachycaulus by GISH. Chromosomes 1A and 1H(t) stayed univalent in all metaphase I cells analyzed, suggesting that Robertsonian translocations do not originate from meiotic recombination in centromeric regions with shared DNA sequence homology. At ana-/telophase I, the 1H(t) and 1A univalents underwent either chromosome or chromatid segregation and misdivided in 6 - 7% of the pollen mother cells. None of the ana-/telophases I analyzed had Robertsonian translocations, which were only observed in 2% of the "half tetrads" at ana-/telophase II. The frequency of Robertsonian translocations observed at ana-/telophase II corresponds well with the number of Robertsonian translocations ( 1 - 4%) detected in progenies derived from plants monosomic for group-1 chromosomes of wheat (1A, 1B, and 1D) and 1H(t) of E. trachycaulus. Our data suggest that Robertsonian translocations arise from centric misdivision of univalents at ana-/telophase I, followed by segregation of the derived telocentric chromosomes to the same nucleus, and fusion of the broken ends during the ensuing interkinesis. Copyright (C) 2005 S. Karger AG, Basel.