Criniti A, Simonazzi G, Cassanelli S, Ferrari M, Bizzaro D, Manicardi G C
Dipartimento di Scienze Agrarie, Università di Modena e Reggio Emilia, Reggio Emilia, Italia.
Genetica. 2005 May;124(1):93-8. doi: 10.1007/s10709-004-8154-y.
Chromatin organization in the holocentric chromosomes of the green apple aphid Aphis pomi has been investigated at a cytological level after C-banding, NOR, Giemsa, fluorochrome staining and fluorescent in situ hybridization (FISH). C-banding technique showed that heterochromatic bands are exclusively located on X chromosomes. This data represents a peculiar feature that clearly contradicts the equilocal distribution of heterochromatin typical of monocentric chromosomes. Moreover, silver staining and FISH carried out with a 28S rDNA probe localized rDNA genes on one telomere of each X chromosome; CMA3 staining reveals that these silver positive telomeres are the only GC-rich regions among A. pomi heterochromatin, whereas all other C-positive bands are DAPI positive thus containing AT-rich DNA.
在对苹果绵蚜全着丝粒染色体的染色质组织进行研究时，我们在C显带、核仁组织区（NOR）、吉姆萨染色、荧光染料染色以及荧光原位杂交（FISH）之后，从细胞学层面进行了观察。C显带技术显示，异染色质带仅位于X染色体上。这一数据代表了一个独特的特征，明显与单着丝粒染色体典型的异染色质等位点分布相矛盾。此外，用28S rDNA探针进行的银染和FISH将rDNA基因定位在每条X染色体的一个端粒上；CMA3染色显示，这些银染阳性端粒是苹果绵蚜异染色质中仅有的富含GC的区域，而所有其他C阳性带都是DAPI阳性，因此含有富含AT的DNA。
