Fig. 1

Decondensation treatments with visible effects on metaphase chromosome morphology. a Normal metaphase cell with no treatment. b–d ICRF-193 treated cells at increasing drug concentrations (0.10, 0.25 and 0.50 μM; left to right) show increasingly elongated chromosomes. OA treated cells with (e) early condensation at S and (f) late S phase of cell cycle. g 5-AZC treated metaphase chromosomes showing heterochromatin regions that did not condense (arrows). h Cell from individual with SC phocomelia (mutation in ESCO2 c.604C > T, c.752delA, exon 3) showing premature sister chromatid separation primarily at heterochromatic regions near centromeres and (i) heterochromatic repulsion (arrows) in most pericentromic regions resulting in a railroad track appearance to the chromosomes. Metaphase chromosomes from Cornelia de Lange individual (NIPBL c.5721del5, exon 31) appeared similar to untreated normal cells (panel a)