Analysis of banded human chromosomes and in situ hybridization patterns by scanning force microscopy

Scanning force microscopy was used to analyze banded human chromosomes and in situ hybridization patterns of biotinylated DNA probes. In standard human GTG-banded metaphase chromosome preparations (where GTG is G-banding with trypsin-Giemsa), chromosomal morphology and banding patterns were well preserved during the scanning procedure. The smallest identifiable features were in the range of about 100 nm and are similar to the typical structures seen by electron microscopy. In addition, in situ hybridization of human DNA probes of known chromosomal localization was used to map specific hybridization signals. Imaging of the precipitated crystals at the hybridization site clearly demonstrates the superior resolution of scanning force microscopy compared to conventional microscopy.