Taxonomy of Finfish (1+2)

6.1.5.3 Chromosome Banding Techniques

Chromosome bands are produced due to the variations in longitudinal structure of the chromatids, revealed by various techniques. Q-banding is named after quinacrine mustard, which is a flurchrome that stains the chromosome differentially. C-band stains deeply the centromeric heterochromatic region present in the centromeric zone of a chromosome. Serial bands (popularly called as G- and R- bands) could be seen throughout the chromosomes by treating them with hot saline solution and staining with Giemsa. Techniques are available to demonstrate nuclear organizer region (NOR), where 18S and 28S rRNA genes are clustered. In last few years the radiolabelled DNA probes are replaced by fluorescent lebelled DNA probes for Fluorescent in situ hybridization (FISH) study. This is useful in detecting the chromosomal location of a DNA sequence.