Patent ID: 7838287

Claim:
A library comprising a collection of individual cells, the cells being denoted cell 1 , cell 2 , . . . , wherein i≧2, each cell comprising a concatemer of individual oligonucleotide cassettes, said concatemer comprising a nucleotide sequence of the following formula: [rs 2 -SP--PR-X-TR-SP-rs 1 ] n wherein rs 1 and rs 2 together comprise a rare cutting restriction site, denoted rs 1 -rs 2 , comprising a recognition sequence of 7 to 38 bases where substantially all restriction sites are complete restriction sites recognized by the same enzyme, SP denotes a spacer of 2 to 2500 bases, X denotes an expressible nucleotide sequence, PR denotes a promoter capable of regulating the expression of X in the cell, TR denotes a terminator, and n≧2 and wherein at least one concatemer of cell 1 is different from a concatemer of cell 2 .