C - BINDING TECHNIQUE

 What is Band ...?

A part of chromosome which is clearly distinguishable from its adjacent segment by appearing darker or lighter with various binding method . 

                                                .........( from paris conference in 1971 )

Why to study Banding pattern ...............?

This allow you to smaller pieces of the chromosome ,so that you could identify smaller structural chromosome abnormalities not visible on routing analysis .

                                Fig. 1

Banding techniques:-

                                 Fig. 2

C - Banding technique :- 

A technique of chromosomal staining in which chromosomes are exposed to alkaline and then acid conditions, in order to reveal bands of constitutive heterochromatic that are identified with Giemsa stain.

Step :- 

                             Fig. 3

Representation of a chromosome band :- 

- Each human chromosome has a short arm p ( p - for petit ) and long arm q ( q - for queue ) saparated by a centromere .

- Each chromosome arm has divided into region or cytogenetic band, that can be seen using a microscope and special stains .

- The cytogenetic band are labeled p1, p2, q1, q2, counting from the centromere out toward the telomeres .

- At higher resolutions, sub band can be seen within the bands . The sub band are also numbered from centromere out toward the telomere 

Application :- 

1) Identification of chromosome particularly in insect and plant .

2) Identification of bivalent at diakinesis using both centromere position .

3) Paternity testing .

4) Gene mapping. 

                              Fig. 4