Usov K E, Shelkovnikova T A, Vasserlauf I E, Stegniĭ V N
Tsitologiia. 2008;50(12):1044-9.
Evolutionary rearrangements of pericentromeric heterochromatin among Drosophila melanogaster subgroup species have been investigated. Region-specific DNA library from Drosophila orena ovarian nurse cell chromocenter has been obtained by microdissection of polytene chromosomes. The probe was localized on ovarian nurse cells chromosomes of D. melanogaster subgroup species using fluorescent in situ hybridization. Sequences homologous to the sequences of the DNA-probe were found in chromocenter and pericentromeric regions of D. orena polytene chromosomes; and in all pericentromeric regions of other species with several exceptions. So, there was no labeling on one of the arms of D. simulans chromosome 2 but such sequences were present on telomere of D. erecta chromosome 3 and in regions adjacent to the brightly DAPI-stained heterochromatic blocks of D. yakuba, D. santomea and D. teissieri chromosomes 2 and 3. At S6 stage (secondary reticulate nucleus), the labeled chromatin in D. orena could be found mostly within a restricted area and no such chromatin could be detected throughout the rest of the nucleus. On the contrary, the labeled DNA was spread diffusely in the nuclei of other species at this stage.
已对黑腹果蝇亚组物种着丝粒周围异染色质的进化重排进行了研究。通过对多线染色体进行显微切割，获得了来自奥氏果蝇卵巢滋养细胞染色中心的区域特异性DNA文库。使用荧光原位杂交技术将探针定位在黑腹果蝇亚组物种的卵巢滋养细胞染色体上。在奥氏果蝇多线染色体的染色中心和着丝粒周围区域发现了与DNA探针序列同源的序列；在其他物种的所有着丝粒周围区域也发现了同源序列，但有几个例外。例如，在拟暗果蝇2号染色体的一条臂上没有标记，但在 erecta 果蝇3号染色体的端粒以及雅库布果蝇、圣多美果蝇和泰氏果蝇2号和3号染色体上与亮 DAPI 染色异染色质块相邻的区域存在此类序列。在S6阶段（次级网状核），奥氏果蝇中标记的染色质大多可在一个受限区域内发现，而在细胞核的其余部分未检测到此类染色质。相反，在此阶段，标记的DNA在其他物种的细胞核中呈弥散分布。
