Disclosed are compositions and a method for amplification of nucleic acid
sequences of interest. The disclosed method generally involves
replication of a target sequence such that, during replication, the
replicated strands are displaced from the target sequence by strand
displacement replication of another replicated strand. In one form of the
disclosed method, the target sample is not subjected to denaturing
conditions. It was discovered that the target nucleic acids, genomic DNA,
for example, need not be denatured for efficient multiple displacement
amplification. The primers used can be hexamer primers. The primers can
also each contain at least one modified nucleotide such that the primers
are nuclease resistant. The primers can also each contain at least one
modified nucleotide such that the melting temperature of the primer is
altered relative to a primer of the same sequence without the modified
nucleotide(s). The DNA polymerase can be .phi.29 DNA polymerase.