T-banding is used to stain the telomeric regions of chromosomes for cytogenetic analysis.
Telomeric (or terminal) banding was first reported by Dutrillaux, who used two types of controlled thermal denaturation followed by staining with either Giemsa or acridine orange. The T bands apparently represent a subset of the R bands because they are smaller that the corresponding R bands and are more strictly telomeric. (Gustashaw, 1991).
T Banding by Thermal Denaturation: Method 1
For Fluorescent Observation
Standard culture methods are appropriate. Slides should be aged for a few days prior to staining. With Giemsa (steps 1-4), the chromosomes are pale, unbanded, and difficult to see. With acridine orange staining for various lengths of time, the chromosomes appear as follows: 45 minutes: green at telomeres, otherwise orange; 15 to 20 minutes: green at telomeres, orange areas are less intense; 30 minutes or more: orange color is gone, intercalating R bands appear.
T Banding by Thermal Denaturation: Method 2
Dutrillaux B. Nouveau systeme de marquage chromosomique: Les bands T. Chromosoma 41:395-402, 1973.
Gustashaw, KM. Chromosome Stains. In The ACT Cytogenetics Laboratory Manual, Second Edition, edited by M. J. Barch. The Association of Cytogenetic Technologists, Raven Press, Ltd., New York, 1991.