An adaptation of the Maxam and Gilbert sequencing method to the study of human metaphase chromosomes.

We have adapted the chemical DNA sequencing method developed by Maxam and Gilbert to study human metaphase chromosomes. Particularly, the in situ cytosine-specific chemical cleavage has been assayed. After exhaustive treatments, a C-like banding pattern was consistently shown. Since methyl groups interfere with the cytosine-specific chemical cleavage reaction, we assume that heterochromatin remains resistant as a result of the high level of methylation. On the other hand when moderate treatments are applied, T-bands remain as resistant regions, implying that these domains would be the most intensely methylated regions within euchromatin.