G-banding involves staining protease-treated chromosomes with Giemsa dye and is thought to result from
interactions of both DNA and protein with the thiazine
and eosin components of the stain. The most common Rbanding method involves heat denaturing chromosomes in
hot acidic saline followed by Giemsastaining. This method
is thought to preferentially denature AT-rich DNA and to
stain the under-denatured GC-rich regions. T-banding
identifies a subset of R-bands – the most intensely staining
ones – by employing either a more severe heat treatment
than R-banding. It is thought to identify the GC-richest Rbands, of which approximately half occur at telomeres in
the human genome, hence the name.