Patent ID: 7018793

Claim:
A method for identifying a protein having an activity of interest, comprising: (a) incubating nucleic acids obtained directly without selection from a mixed population of organisms from an environmental source, said nucleic acid has at least a portion of a nucleic acid sequence encoding a molecule of interest, with at least one oligonucleotide probe labeled with a detectable label under such conditions and such time to allow interaction of complementary sequences; (b) identifying nucleic acid sequences having a complement to the oligonucleotide probe using an analyzer that detects the detectable label; (c) generating a library from the identified nucleic acid sequences; (d) screening the library for a specified activity; (e) mutating a nucleic acid sequence contained in a clone from the library having the specified activity; and (d) comparing the activity of an expression product of the clone from (e) following mutation with the specified activity of an expression product of the clone without mutation, wherein a difference in the activity is indicative of an effect of introducing at least one sequence mutation, thereby identifying a protein having an activity of interest.