What is the general principle of PCR-SSP? I get it uses sequence-specific primers to bind only to selected alleles but isn't this the principle in all PCR techniques?

Without giving the answer away, see if you understand the following and think what is meant by an allele in terms of gene sequence:

Rev Immunogenet. 1999;1(2):157-76.

Molecular typing for the MHC with PCR-SSP.

Welsh K¹, Bunce M.

Abstract

Sequence-specific amplification (SSP) is simply a form of polymerase chain reaction (PCR) which involves designing one or both primers so that they will or will not allow amplification (the 3'-mismatch principle). Its origins are probably legion, i.e. many people probably thought of it at the same time. For example, in 1988 a group from Guy's Hospital, London, described a form of SSP for HLA-DR4 detection and in the same year a group from Upjohn described its use at the American Society of Histocompatibility and Immunogenetics (ASHI). Both are published in abstract form (British Society of Rheumatology and ASHI). The 3'-mismatch principle can be used to identify virtually any single nucleotide point mutation (SNP) within one or two PCR-SSP reactions and the first peer-reviewed statements of this came in 1989 (1, 2). Thus, although the use of SSP probably began around 1990, it was 5 years before its popularity erupted, mainly due to the work of Olerup & Zetterquist (3, 4), who defined its potential for solid organ transplantation. It is now the method of choice for high resolution HLA typing in many laboratories. In addition, over a thousand applications for genes outside the MHC are in the literature.

https://www.ncbi.nlm.nih.gov/pubmed/11253945

 

 

thanks for the reply, I got there eventually.