Transgenic animal for production of antibodies having minimal CDRS

A transgenic chicken comprising a genome comprising a recombinant immunoglobulin light chain (IgL) locus comprising:

• a) a functional IgL gene comprising a nucleic acid encoding a light chain variable region comprising:
• i) a light chain CDR1, CDR2 and CDR3 regions;
• and
• ii) a light chain framework;
• and
• b) a plurality of pseudogenes that encode light chain variable regions each comprising:
• i) a light chain CDR1, CDR2 and CDR3 regions;
• and
• ii) a light chain framework region that is identical in amino acid sequence to the light chain framework of a) (ii);
• wherein said recombinant IgL locus comprises:
• in operable linkage:
• an intron region, a constant domain region-encoding region and a 3′ untranslated region;
• wherein at least part of said intron region is endogenous to the genome of said transgenic chicken;
• and said nucleic acid of a) and pseudogene of b), are exogenous to the genome of said transgenic chicken,
• wherein each amino acid residue of the CDRs encoded by the pseudogenes of b) and each amino acid residue of the CDRs of the light chain variable region of a) are selected from the same group of 2 to 5 amino acid residues,
• wherein said plurality of pseudogenes are operably linked to said functional IgL gene and donate nucleotide sequences to the nucleic acid of a) by gene conversion in said transgenic chicken;
• and
• wherein said transgenic chicken expresses a recombinant immunoglobulin comprising a diversified form of said functional IgL variable region.