**10. Limitations of PCR**

Since it discovery in 1980s, the PCR technique has brought about significant changes in biological sciences. Huge scientific undertakings like the Human Genome Project have been possible due to PCR-based approaches [5, 6]. It is a very sensitive

**25**

**Author details**

Shaheen Shahzad1

Pakistan

\*, Mohammad Afzal<sup>2</sup>

usually take much longer time than the PCR reaction itself.

2 Consultant for Health Research and M&E, Pakistan

\*Address all correspondence to: drshaheen@iiu.edu.pk

provided the original work is properly cited.

1 Genomics Research Lab, Department of Bioinformatics and Biotechnology, Faculty of Basic and Applied Sciences, International Islamic University, Islamabad,

3 Department of Biology, Lahore Garrison University, Lahore, Pakistan

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Shomaila Sikandar3

and Imran Afzal3

*Polymerase Chain Reaction*

*DOI: http://dx.doi.org/10.5772/intechopen.81924*

and flexible technique to amplify DNA of interest. A very small amount of the target DNA can be used as a starting material. Even old or degraded DNA samples may yield successful amplification. However, there is also a long list of PCR limitations. High-quality DNA amplification needs information about target DNA sequence. The sensitivity of PCR is also its major disadvantage since the very end result of a PCR is highly susceptible to contamination or false amplification. Therefore, amplification of DNA by PCR may not be 100% specific. Moreover, the specificity of amplification is dependent on physicochemical parameter, such as temperature and Mg++ concentration. The PCR is also inhibited by the presence of certain chemicals such as ethanol, phenol, isopropanol, detergent compounds like sodium dodecyl sulfate (SDS), high salt concentration, chelators, etc. There is an upper limit to the size of DNA that can be synthesized by PCR. Additionally, analysis and product detection
