Competitive blocker pcr

[Kimberly Lieuallen]

Hello everyone,
We are interested in utilizing competitive blocker pcr to screen
bacterial colonies for the presence or absence of a transposon in 
the insert. I have read an abstract entitled: Allele-specific 
competitive blocker PCR: a one-step method with applicability to pool 
screening by Orou, A, et al. In this procedure three primers are used 
in the same pcr reaction but one primer acts as a blocker to 
amplification since the 3' end of the primer is labelled with a 
dideoxynucleotide. In their paper, the "crippled" primer successfully 
blocked the wildtype allele, so that only detection of the mutant 
alleles resulted.
Has anyone has experience with this method? Is the amplification of 
the wildtype allele practically undetectable? 
If anyone has experience success/disgust with this method please email 
me at: lieuallen1 at llnl.gov
Thanks,
Kim