Dubrovnaia O V, Tishchenko E N
Tsitol Genet. 2003 Nov-Dec;37(6):23-30.
Cytogenetic characters and the level of DNA methylation were studied in sugarbeet callus cultures with different morphogenic potential which were obtained from the same leaf explant. It was shown that non-morphogenic callus in comparison with the morphogenic one was characterized by the higher level of cell ploidy and of the frequency of chromosome structural rearrangements even at the early stages of cultivation. Overspiralization of chromosomes and formation of condensed chromatin were observed in polyploid cells of non-morphogenic callus. At the same time cytosine hypermethylation occurs in site-specific CpCpGpG-sequences of DNA indicating the possible role of this DNA modification in the processes of genome rearrangements.
对从同一叶片外植体获得的具有不同形态发生潜力的甜菜愈伤组织培养物的细胞遗传学特征和DNA甲基化水平进行了研究。结果表明，与形态发生愈伤组织相比，非形态发生愈伤组织即使在培养早期也具有较高的细胞倍性水平和染色体结构重排频率。在非形态发生愈伤组织的多倍体细胞中观察到染色体过度螺旋化和浓缩染色质的形成。同时，DNA的位点特异性CpCpGpG序列中发生了胞嘧啶高甲基化，表明这种DNA修饰在基因组重排过程中可能发挥作用。
