A process for the production of an antigen specific antigen binding molecule using a transformed host containing a library of expressible DNA sequences encoding a plurality of antigen specific antigen binding molecules wherein the library is created from at least two heterologous isotype novel antigen receptor sequences, wherein the antigen specific antigen binding molecules comprise a plurality of domains of a variable region of the immunoglobulin isotype NAR found in a member of a species in the Elasmobranchii subclass, wherein the antigen specific antigen binding molecules have a peptide domain structure represented by the following formula: FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 and wherein the library of expressible DNA sequences is produced by a method comprising the following steps: isolating RNAfrom a member of a species in the Elasmobranchii subclass; amplifying DNA sequences from RNA obtained in which encode antigen specific antigen binding molecules to create a database of DNA sequences encoding antigen specific binding molecules; selecting a DNA sequence from the database prepared in; amplifying DNA sequences encoding two or more contiguous peptide domains of FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 wherein said two or more contiguous peptide domains when ligated encode an antigen specific antigen binding molecule of formula and where said two or more contiguous peptide domains are from at least two heterologous isotype NAR DNA sequences selected in in the presence of a plurality of heterologous oligomers complementary to CDR1 or CDR3 domains in sequences selected in to form a plurality of amplified DNA sequences encoding an antigen specific antigen binding molecule of formula; ligating together said amplified DNA sequences encoding two or more contiguous peptide domains to form DNA sequences encoding an antigen specific binding molecule having the peptide domain structure of formula; cloning the amplified DNA obtained in into a display vector; and transforming a host with said display vector to produce a library of said antigen specific antigen binding molecules. isolating RNAfrom a member of a species in the Elasmobranchii subclass; amplifying DNA sequences from RNA obtained in which encode antigen specific antigen binding molecules to create a database of DNA sequences encoding antigen specific binding molecules; selecting a DNA sequence from the database prepared in; amplifying DNA sequences encoding two or more contiguous peptide domains of FW1-CDR1-FW2-HV2-FW3a-HV4-FW3b-CDR3-FW4 wherein said two or more contiguous peptide domains when ligated encode an antigen specific antigen binding molecule of formula and where said two or more contiguous peptide domains are from at least two heterologous isotype NAR DNA sequences selected in in the presence of a plurality of heterologous oligomers complementary to CDR1 or CDR3 domains in sequences selected in to form a plurality of amplified DNA sequences encoding an antigen specific antigen binding molecule of formula; ligating together said amplified DNA sequences encoding two or more contiguous peptide domains to form DNA sequences encoding an antigen specific binding molecule having the peptide domain structure of formula; cloning the amplified DNA obtained in into a display vector; and transforming a host with said display vector to produce a library of said antigen specific antigen binding molecules.