Chromosomes in a genome-wise order: evidence for metaphase architecture.

Background: One fundamental finding of the last decade is that, besides the primary DNA sequence information there are several epigenetic "information-layers" like DNA-and histone modifications, chromatin packaging and, last but not least, the position of genes in the nucleus.

Results: We postulate that the functional genomic architecture is not restricted to the interphase of the cell cycle but can also be observed in the metaphase stage, when chromosomes are most condensed and microscopically visible. If so, it offers the unique opportunity to directly analyze the functional aspects of genomic architecture in different cells, species and diseases.

Identification of parental chromosomes involved in translocations BCR-ABL, t(9;22) and PML-RARA, t(15;17).

Cells of blood and bone marrow often exhibit a genome- or ploidywise organization of the two haploid sets, representing apparently maternal and paternal chromosomes in interphase nuclei and in metaphase spreads. This provides the opportunity to perform "genomic karyotyping." Such application of karyotyping may indicate whether two chromosomes involved in a translocation are both maternal, both paternal, or intermingled, i.

Biphasic chromatin structure and FISH signals in reflect intranuclear order.

Background And Aim: One of the two parental allelic genes may selectively be expressed, regulated by imprinting, X-inactivation or by other less known mechanisms. This study aims to reflect on such genetic mechanisms.

Materials And Methods: Slides from short term cultures or direct smears of blood, bone marrow and amniotic fluids were hybridized with FISH probes singly, combined or sequentially.