Genome variation in the trophoblast cell lifespan: Diploidy, polyteny, depolytenization, genome segregation

Figure 5 Distribution of heterochromatin blocks into nuclear fragments of mouse trophoblast giant cells. A: The initial nucleus (In) of trophoblast giant cells (TGC) in the process of fragmentation; B: The initial nucleus contains large clear-cut heterochromatin blocks (Hn, arrows) near nucleoli (Nl); C: The nucleus contains non-classic polytene chromosomes with numerous distal loops (arrowheads); D and E: Nuclear fragments with small heterochromatin blocks (arrows) near nucleoli. Squash preparations, aceto-orcein staining. Fr: Nuclear fragments.