SOUTHERN HYBRIDIZATION / BLOTTING .....

 What is blotting ( hybridization )........?

The term blotting refers to the transfer of biological sample from a gel to membrane and their subsequent detection on the surface of the membrane . 

- Technique for transferring DNA, RNA and protein onto a carrier they can be separated ,and often follow the use of a gel electrophoresis.

What is nucleic acid hybridization .....? 

A technique in which single stranded nucleic acids ( DNA, RNA) are allowed to interact so that complexes called hybrids are formed by molecule with similar , complementary sequences .

Type of blotting :-

1) Southern blotting 

2) Northern blotting 

3) Western blotting 

SOUTHERN BLOTTING :-

- It is method used in molecular biology for DNA analysis .

- The method is named after its inventor the British biologist Edwin mellor southern , in 1975.

- This method is also known as DNA blotting .

Step involved in southern blotting :-

1) Extract and purify DNA from cell .

2) DNA is restricted with enzyme .

3) Separated by electrophoresis .

4) Denature DNA .

5) Transfer to nitrocellulose paper .

6) Add labelled probe for hybridization to take place .

7) Wash off unbound probe .

8) Autoradiograph .

Schematic view of southern hybridization :-

Application :-

- To isolate specific DNA in a DNA sample .

- To isolated desired DNA for construction of r DNA .

- Identify mutation , deletion , and gene rearrangement .

- Used in prenatal diagnosis of genetic diseases .

- In RFLP.

- In DNA fingerprinting .

     : paternity and maternity testing 

     : criminal identification and forensics .

Advantages :-

- Effective way to detect a specific DNA sequence in a large complex sample of DNA.

- Can be used to quantify the amount of the present DNA .

- Cheaper than DNA sequencing .

Disadvantages :- 

- Complex and labor intensive .

- Time consuming .