Department of Plant Anatomy and Cytology, University of Silesia, Katowice, Poland.
Genome. 2011 Sep;54(9):710-7. doi: 10.1139/g11-035. Epub 2011 Aug 17.
The chromosomal organization of two novel repetitive DNA sequences isolated from the Chenopodium quinoa Willd. genome was analyzed across the genomes of selected Chenopodium species. Fluorescence in situ hybridization (FISH) analysis with the repetitive DNA clone 18-24J in the closely related allotetraploids C. quinoa and Chenopodium berlandieri Moq. (2n = 4x = 36) evidenced hybridization signals that were mainly present on 18 chromosomes; however, in the allohexaploid Chenopodium album L. (2n = 6x = 54), cross-hybridization was observed on all of the chromosomes. In situ hybridization with rRNA gene probes indicated that during the evolution of polyploidy, the chenopods lost some of their rDNA loci. Reprobing with rDNA indicated that in the subgenome labeled with 18-24J, one 35S rRNA locus and at least half of the 5S rDNA loci were present. A second analyzed sequence, 12-13P, localized exclusively in pericentromeric regions of each chromosome of C. quinoa and related species. The intensity of the FISH signals differed considerably among chromosomes. The pattern observed on C. quinoa chromosomes after FISH with 12-13P was very similar to GISH results, suggesting that the 12-13P sequence constitutes a major part of the repetitive DNA of C. quinoa.
从藜科基因组中分离的两个新的重复 DNA 序列的染色体组织，在选定的藜科物种的基因组中进行了分析。用重复 DNA 克隆 18-24J 进行荧光原位杂交（FISH）分析，在密切相关的异源四倍体藜（Chenopodium quinoa）和 Chenopodium berlandieri Moq.（2n = 4x = 36）中，杂交信号主要存在于 18 条染色体上；然而，在异源六倍体藜（Chenopodium album L.）（2n = 6x = 54）中，观察到所有染色体的交叉杂交。rRNA 基因探针的原位杂交表明，在多倍体进化过程中，藜科植物失去了一些 rDNA 基因座。rDNA 的重新探测表明，在被 18-24J 标记的亚基因组中，存在一个 35S rRNA 基因座和至少一半的 5S rDNA 基因座。分析的第二个序列 12-13P，仅定位于藜和相关物种每条染色体的着丝粒周围区域。FISH 与 12-13P 后，在藜科染色体上观察到的 FISH 信号强度差异很大。用 12-13P 进行 FISH 后在藜科染色体上观察到的模式与 GISH 结果非常相似，表明 12-13P 序列构成了藜科重复 DNA 的主要部分。
