The invention provides methods, kits, and compositions comprising novel mutant loxP sites. Such sites are particularly useful for procedures requiring multiple site-specific recombination reactions, including deletions or insertions of multiple genes or other sequences in the same organism, staged insertions or deletions of genes of the same organism at different times, assembly of large polynucleotide constructs by serial site-specific recombination, and the like. In one aspect, compositions of the invention includes particular mutant spacer oligonucleotides of loxP recombination elements, the recombination elements themselves, and pairs of non-promiscuous mutant loxP sites.