Patent ID: 7288375

Claim:
A method for selecting from or screening a library of recombinant proteins to identify a recombinant protein having a desired functional property, said method comprising: a) randomly fragmenting a template double-stranded DNA into a plurality of double-stranded fragments of a desired size; b) adding to said plurality of double-stranded fragments one or more single- or double-stranded oligonucleotides, wherein said single- or double-stranded oligonucleotides comprise areas of identity and areas of heterology to the template double-stranded DNA; c) denaturing said plurality of double-stranded fragments and said oligonucleotides to form a population of single-stranded fragments; d) incubating said population of single-stranded fragments from step c) with a polymerase under conditions which result in the annealing of said single-stranded fragments at said areas of identity to form pairs of annealed fragments, said areas of identity being sufficient for one member of a pair to prime replication of the other member of the pair, thereby forming mutagenized double-stranded DNA molecules; e) repeating steps c) and d) for a desired number of cycles, wherein repeated step c) further comprises denaturing the mutagenized double-stranded DNA molecules formed in step d) in previous cycles, thereby forming a library of mutagenized double-stranded DNA molecules; f) expressing a library of recombinant proteins encoded by said library of mutagenized double-stranded DNA molecules from step e); and g) selecting or screening said library of recombinant proteins to identify a recombinant protein with a desired functional property.