Tandem repeats of Allium fistulosum associated with major chromosomal landmarks
Tandem repeats of Allium fistulosum associated with major chromosomal landmarks
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DOI：
10.1007/s00438-016-1286-9
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发表时间：
2017-04-01
影响因子：
3.1
通讯作者：
Khrustaleva, Ludmila I.
中科院分区：
文献类型：
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作者：
Kirov, Ilya V.;Kiseleva, Anna V.;Khrustaleva, Ludmila I.
串联重复序列通常与重要的染色体标志物有关，如着丝粒、端粒、亚端粒和其他异染色质区域，可以作为分子细胞遗传学标记的良好候选者。存在于许多植物物种中的串联重复序列在单位长度、在基因组中的比例和染色体组织上表现出显著的差异。洋葱属的成员及其庞大的基因组对当前的遗传学来说是一项具有挑战性的任务。利用下一代测序数据、分子和细胞遗传学方法，我们在大葱基因组(2n=2C=16)中发现了两个重复序列，HAT58和CAT36。这些重复序列加在一起，构成了聚集洋葱基因组的0.25%，其中16万个拷贝/1C的HAT58和93,000个拷贝/1C的CAT36。荧光原位杂交(FISH)和C-显带分析表明，HAT58和CAT36与华支睾吸虫第5、6、7和8号染色体的间质和着丝粒周围异染色质相关。用HAT58和CAT36对洋葱(2n=2C=16)和洋葱(2n=2C=16)进行FISH，发现这些重复序列是物种特有的，只在华支睾吸虫染色体上产生特异的杂交模式。因此，这些标记可用于监测外来遗传物质的种间育种计划。我们应用了非变性FISH，可以在3小时内检测到带有重复序列的染色体。观察到HAT58染色体位置的多态。这一发现表明，HAT58重复序列的快速进化仍在进行中。
Tandem repeats are often associated with important chromosomal landmarks, such as centromeres, telomeres, subtelomeric, and other heterochromatic regions, and can be good candidates for molecular cytogenetic markers. Tandem repeats present in many plant species demonstrate dramatic differences in unit length, proportion in the genome, and chromosomal organization. Members of genus Allium with their large genomes represent a challenging task for current genetics. Using the next generation sequencing data, molecular, and cytogenetic methods, we discovered two tandemly organized repeats in the Allium fistulosum genome (2n = 2C = 16), HAT58 and CAT36. Together, these repeats comprise 0.25% of the bunching onion genome with 160,000 copies/1 C of HAT58 and 93,000 copies/1 C of CAT36. Fluorescent in situ hybridization (FISH) and C-banding showed that HAT58 and CAT36 associated with the interstitial and pericentromeric heterochromatin of the A. fistulosum chromosomes 5, 6, 7, and 8. FISH with HAT58 and CAT36 performed on A. cepa (2n = 2C = 16) and A. wakegi (2n = 2C = 16), a natural allodiploid hybrid between A. fistulosum and A. cepa, revealed that these repeats are species specific and produced specific hybridization patterns only on A. fistulosum chromosomes. Thus, the markers can be used in interspecific breeding programs for monitoring of alien genetic material. We applied Non-denaturing FISH that allowed detection of the repeat bearing chromosomes within 3 h. A polymorphism of the HAT58 chromosome location was observed. This finding suggests that the rapid evolution of the HAT58 repeat is still ongoing.