What staining technique is most useful in determining the chromosomal origin of a small extra marker with satellites?

The use of the Nucleolar Organizer Region (NOR) staining technique is particularly effective for identifying the chromosomal origin of small extra markers, especially those with associated satellites. This technique highlights the presence of nucleolar organizer regions, which are chromosomal loci that play a crucial role in ribosomal RNA (rRNA) synthesis and are often located on acrocentric chromosomes.

When a small extra marker contains satellites, this typically indicates that it may derive from an acrocentric chromosome, such as chromosomes 13, 14, 15, 21, or 22. By employing NOR staining, these regions can be visualized distinctly, allowing cytogeneticists to ascertain whether the extra marker corresponds to an acrocentric chromosome by revealing its nucleolar organizer characteristics.

In contrast, the other techniques do not provide the same specific chromosomal identification for small extra markers. Giemsa stain is more general and primarily useful for creating a karyotype and identifying chromosome structure. Fluorescence in situ hybridization (FISH) is excellent for detecting specific DNA sequences but may not be as effective in establishing the origin of very small or ambiguous markers without known sequence targets. Comparative Genomic Hybridization (CGH) is a whole-genome approach used