Sunday, June 12, 2011

Optimization of PCR

Optimization of PCR is a tedious and hectic job sometime you get results very early and some time it takes too long time. I was facing the same problem when I encountered with this method. When I read this I found it a simple, fast and reliable method for the optimization of PCR. It is called the Taguchi methods. It is a statistical method developed by Genichi Taguchi to improve the quality of manufactured goods, but now it is also used in engineering, biotechnology, marketing and advertising.

With the use of Taguchi methods, the range of optimal conditions for any given PCR assay may be obtained in very little number of reactions required to optimize several different variables in a classical block titration method.

For example if 4 different variables (like dNTPs, Mg++, primer, enzyme or you can put some other variables) are tested at 3 different concentrations each, the titration would need 3X3X3X3 = 81 reactions.

However, using Taguchi methods, only 9 reactions are required.

In this method, the number of reactions (E) is calculated from   E = 2k + 1; where k being the number of variables to be tested.

Now if we increase the number of variables, for example if there are 8 variables, than we need 6561 reactions in block titration method, but only 17 reactions are needed with the use of the Taguchi method. 


Table 1
Table 2




A
B
C
Primer
7.5
15
30
MgCl2
0.5
1.5
3
dNTPs
50
100
200
Enzyme
0.5
2
5


For more details please see the following article.



Cobb, B.D., Clarkson, J.M. 1994. A simple procedure for optimizing the polymerase chain reaction using modified Taguchi methods Nucl Acids Res., 22(18): 3801-38