Highly condensed potato pericentromeric heterochromatin contains rDNA-related tandem repeats.
Highly condensed potato pericentromeric heterochromatin contains rDNA-related tandem repeats.
复制标题
高度浓缩的马铃薯着丝粒周围异染色质含有 rDNA 相关串联重复序列。
作者：
R. Stupar;Junqi Song;Ahmet L Tek;Zhukuan Cheng;F. Dong;Jiming Jiang
真核生物基因组中的异染色质代表基因缺失区域，含有高度重复的DNA序列。人们对异染色区DNA序列的起源和进化知之甚少。在这里，我们报道了一类独特的着丝粒异染色质，它由与马铃薯18S.25S核糖体RNA基因的基因间隔区(IGS)高度同源的DNA序列组成。从二倍体马铃薯种球茎茄子中分离到一个5.9kb的串联重复序列，命名为2D8。序列分析表明，该2D8重复序列与马铃薯rDNA的IGS相关。该重复序列与高度浓缩的着丝粒周围异染色质在几个半合子基因座上有关。在整个茄属植物中，2D8重复序列在结构和拷贝数上都有很大的变化，这表明它在进化上是动态的。在马铃薯基因组中还发现了其他与IGS相关的重复DNA元件。讨论了IGS相关重复序列起源和演化的可能机制。我们证明马铃薯是研究重复DNA家族的一个有趣的模型，因为它是无性繁殖的，从而最小化了可以移除新DNA重复的减数分裂机制。
The heterochromatin in eukaryotic genomes represents gene-poor regions and contains highly repetitive DNA sequences. The origin and evolution of DNA sequences in the heterochromatic regions are poorly understood. Here we report a unique class of pericentromeric heterochromatin consisting of DNA sequences highly homologous to the intergenic spacer (IGS) of the 18S.25S ribosomal RNA genes in potato. A 5.9-kb tandem repeat, named 2D8, was isolated from a diploid potato species Solanum bulbocastanum. Sequence analysis indicates that the 2D8 repeat is related to the IGS of potato rDNA. This repeat is associated with highly condensed pericentromeric heterochromatin at several hemizygous loci. The 2D8 repeat is highly variable in structure and copy number throughout the Solanum genus, suggesting that it is evolutionarily dynamic. Additional IGS-related repetitive DNA elements were also identified in the potato genome. The possible mechanism of the origin and evolution of the IGS-related repeats is discussed. We demonstrate that potato serves as an interesting model for studying repetitive DNA families because it is propagated vegetatively, thus minimizing the meiotic mechanisms that can remove novel DNA repeats.
影响因子：
3.1
作者：
BENNETZEN, JL;SCHRICK, K;SANMIGUEL, P
通讯作者：
SANMIGUEL, P
影响因子：
7.2
作者：
Copenhaver, GP;Pikaard, CS
通讯作者：
Pikaard, CS