Recombination of insertion modified nucleic acids

A method of recombining a plurality of sequence domains from a plurality of homologous or non-homologous parental nucleic acids, the method comprising:

• recursively recombining the plurality of homologous or non-homologous parental nucleic acids, thereby providing a plurality of artificially recombined nucleic acids;
• transcribing the plurality of artificially recombined nucleic acids, thereby providing pre-mRNAs each comprising a plurality of sequence domains which correspond to a plurality of different parental nucleic acid sequences;
• and,
• alternatively splicing the pre-mRNAs to produce from each of the pre-mRNAs a plurality of different mRNAs comprising a plurality of different sets of sequence domains.