Special
Stains (may be added to any chromosome study)
R-banding procedures
produce the reverse or opposite banding pattern as G-banding
and Q-banding and denotes the GC-rich euchromatic regions. R-bands
are important for detecting minor inversions, for comparing length
of homologs, for examining the ends of chromosomes, and for identifying
subtle deletions or rearrangements that may go undetected using
G- or Q-bands.
Q-banding methods produce fluorescent bands after staining
chromosome preparations with quinacrine. These bands represent
the AT-rich regions of the chromosome and are analogous to the
bands produced by G-banding. Q-banding is particularly useful
in identifying polymorphisms on the satellites of the acrocentric
chromosomes and of the Y chromosome, and in confirming translocations
involving the Y.
C-banding is a procedure which stains the constitutive
heterochromatin that is localized in pericentromeric regions
of all chromosomes and on distal long arm of the Y. C-banding
is useful in confirming pericentric inversions and in identifying
polymorphisms of the centromeric regions of chromosomes 1, 9
and 16 and the heterochromatic region of the Y, and in confirming
translocations involving the Y.
NOR staining is a silver staining procedure which stains
the nucleolus organizer regions (NORs) of satellited chromosomes.
It is particularly useful in studying variations in the size
of the stalks and satellites of the acrocentric chromosomes.
DAPI staining produces bright fluorescence of the heterochromatic
regions of chromosomes 1, 9, 16, Y, and the centromeric region
of 15. It is particularly helpful in identifying the origin of
small bisatellited marker chromosomes and in confirming translocations
involving the heterochromatic region of Y.
CPT codes: Special
Stains (each): 88283 plus appropriate codes for tissue type
studied.
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