Pericentromeric GC-rich chromatin in Rhoeo (Commelinaceae). Evidence from soma and germ-line

Abstract

— CMA/DA/DAPI technique revealed the presence of GC-rich regions in mitotic/meiotic chromosomes and within meiotic collective chromocenters of permanent heterozygote Rhoeo spathacea (2n = 12). CMA-bands were detected within some NOR-related chromosome ends and within all twelve pericentromeric regions. It can not be excluded that GC-rich segments associated with AT-rich pericentromeric heterochromatin may serve as landmarks of the putative translocation breakpoints in this species. The persistence of two cytologically well-defned chromatin domains (AT and GC-rich) within pericentromeres of all chromosomes suggests spreading and homogenization of their sequences during evolution of Rhoeo karyotype.

Key words:

• centromeres
• meiosis
• multivalent
• Rabl orientation
• Rhoeo spathacea
• translocations