chapter  9
10 Pages

Identification of Chromosome Segments

WithArchana Sharma, Sumithra Sen

Analysis of the different gene blocks in chromosomes and segments of complex genome has been carried out through the development and use of probes with differential fluorescence. In the identification of chromosome segments, the study of linear banding patterns in the chromosomes has emerged as a powerful tool. In certain cases, even functionally differentiated regions of chromosome, such as ribosomal or nucleolar regions, have specific banding patterns. T. Caspersson and his colleagues noted that treatment with quinacrine dyes revealed strongly fluorescent chromosome segments when viewed through ultraviolet (UV) light. The chemical basis of giemsa banding is derived primarily from the fact the G bands are comparable to Q bands after treatment with fluorescent compounds and observed under UV light. Importance of the DNA-protein linkage, as in G banding, is also noted in orcein banding, where the pattern is the same.