2.3. EIV-specific primer design using primers4clades and MPprimer
Based on the above mentioned rationale, primers4clades (Contreras-Moreira et al., 2009), which is based on the CODEHOP (Consensus Degenerate HybridOligo-nucleotide Primer) primer design strategy (Rose, 2005 and Rose et al., 1998) of designing primers based on clades, was used to design EIV-specific primers among complex lineage groups. However, due to the limited number of input sequences for the analysis, representative influenza viral sequences isolated at different years in various continents and consensus sequences from each distinct lineage were used to generate candidate primer sets. Using the program, the sequences were analyzed under the cluster sequences (i.e., advanced mode) with some parameter changes (i.e., a suitable Tm (55 °C) for the consensus clamp, GTR + G model, and 250–750 amplicons) to find optimized primers and PCR regions. Additionally, to design four multiplex PCR primer sets, MPprimer (Shen et al., 2010) was employed to search appropriate PCR regions and primer sets for each segment. Results obtained from both applications were investigated in complement to each other, and overlapping or similar PCR regions and primer sets were selected.