“…It has been reported that VNARs can be isolated from libraries of immune ( 30 , 47 , 48 ), naïve ( 45 , 55 ), synthetic ( 41 ), or semi-synthetic origin ( 56 ) ( Figure 1 ). The diversity of the VNAR libraries screened in the reviewed works was 50% from natural immune sources ( 38 , 39 , 43 , 46 ), 37.5% from synthetic origin ( 34 , 35 , 40 ), and 12.5% from natural naïve (non-immunized) source ( 44 ). Whereas the immune libraries screened in the reviewed papers were constructed using similar protocols for immunization and amplification of the shark immune repertoire, the synthetic libraries screened were constructed by different methodologies.…”