Hi, the same question: https://www.researchgate.net/post/What_is_the_PCR_amplification_of_specific_alleles_PASA_method

And one link: http://www.biotechniques.com/BiotechniquesJournal/2010/February/DNA-and-General-PCR-Methods-Allele-specific-PCR/biotechniques-187817.html

Cheers, Nadine

Allele specific amplification differs from the normal PCR in that primers are carefully designed to target the region of difference in the different alleles so that a pair of primers only amplify a specific allele but not others. 

Please see the website:http://www.biotechniques.com/multimedia/archive/00085/BTN_A_000113361_O_85089a.pdf.

Thank you for guidance.

You can please follow the links below to obtain certain valuable informations:-

1. http://www.biomedcentral.com/1471-2350/14/27

2. http://www.ncbi.nlm.nih.gov/pubmed/19768609

3. http://www.pnas.org/content/98/1/206.long

4. http://www.ncbi.nlm.nih.gov/pubmed/7686270