  This paper reports some experimental results validating in a broader context
a variant of PCR, called XPCR, previously introduced and tested on relatively
short synthetic DNA sequences. Basic XPCR technique confirmed to work as
expected, to concatenate two genes of different lengths, while a library of all
permutations of three different genes (extracted from the bacterial strain
Bulkolderia fungorum DBT1) has been realized in one step by multiple XPCR.
  Limits and potentialities of the protocols have been discussed, and tested in
several experimental conditions, by aside showing that overlap concatenation of
multiple copies of one only gene is not realizable by these procedures, due to
strand displacement phenomena. In this case, in fact, one copy of the gene is
obtained as a unique amplification product.
