Interchromatidal central ridge and transversal symmetry in early metaphasic human chromosome one

The topographic structure of Giemsa-banded (G-banded) early metaphase human chromosomes adsorbed on glass was analyzed by atomic force microscope using amplitude modulation mode (AM-AFM). Longitudinal height measurements for early metaphasic human chromosomes showed a central ridge that was further characterized by transversal height measurements. The heterochromatic regions displayed a high level of transversal symmetry, while the euchromatic ones presented several peaks across the transversal height measurements. We suggest that this central ridge and symmetry patterns point out a transitional arrangement of the early metaphase chromosome and support evidence for interchromatidal interactions prior to disjunction.