**7. Chromosome banding application**

*Cytogenetics - Classical and Molecular Strategies for Analysing Heredity Material*

information [37].

larger or maximum in quantity and quality. The tool of image linearization enables a better visualization technique which ultimately extends and refines the information that can be extracted from the chromosomes (**Figure 6**). For example, conventional chromosome bands ➔ enough bands for analysis ➔ molecular banding techniques ➔ more bands, more differentiation, more information ➔ computational techniques (software packages) ➔ better organization of cytogenetic data ➔ tool of image linearization ➔ still more bands, still more differentiation, still more

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**Figure 6.**

*Characteristics of chromosome linearization and differentiation banding technique.*

The chromosome banding primarily could be used for the detection and recognition of nature and type of the aberrations, identification of the chromosome involved and most importantly, the location of the presumptive positions of the lesions (usually termed as break points) involved in the structural changes in chromosome complements [38].

The basic requirement for the detection of chromosomal structural changes using the banding methods is disruption in the normal sequential band pattern of a chromosome arm region. The disruption in the chromosomal arm may take several forms and the most common forms are presence of an additional band, absence of an expected band, unexpected change in banding pattern and reversion of a part of banding pattern. The basic requirements for the chromosomal structural changes are possible by the existence of consistent and fixed pattern of chromosomal bands on chromosomal arm region as well as existence of good sequential differentiation between the chromosomal arm bands. Chromosome condensation is a process that occurs as the cell progresses towards metaphase and continues till the cells are held at metaphase by the action of spindle inhibiting chemicals. Consequently, number of bands, banding pattern, clarity and differentiation among the bands would be a function of state of chromosome contraction and possible provides the existence of consistent and fixed pattern of chromosomal bands at metaphase on chromosomal arm region. The good sequential differentiation between the chromosomal arm bands may cause differences in size, staining intensity, longitudinal spacing, numerical concentration of dark and light bands which forms the basis for the identification of individual chromosomes, but sometimes, the quality of differentiation varies between treatments and also between the cells on the same slide by application of different staining and banding procedures [39].
