G-banded Human Chromosomes Observed by Atomic Force Microscopy

摘要

The structure of G-bands of human metaphase chromosomes was observed by light microscopy and atomic force microscopy (AFM). Air-dried chromosomes after G-band staining showed alternating ridges and grooves on their surface, which correspond to G-positive and G-negative bands respectively. G-positive ridges were composed of densely packed chromatin fibers, while the fibers were loose in G-negative grooves. Fibers bridging the gap between sister chro-matids of a mitotic pair were restricted within the G-positive portions. These findings indicate that the G-banding pattern reflects the high-order structure of chromosomes, which is expected to be analyzed more precisely by AFM.