The invention relates to a procedure for linking cognate pairs of VH and VL encoding sequences from a population of cells enriched in particular surface antigen markers. The linking procedure involves a multiplex molecular amplification procedure capable of linking nucleotide sequences of interest in connection with the amplification, in particular polymerase chain reaction (multiplex PCR). The method is particularly advantageous for the generation of cognate pair libraries as well as combinatorial libraries of variable region encoding sequences from immunoglobulins. The invention also relates to methods for generation of chimeric human/non-human antibodies and expression libraries generated by such methods.