We are constructing a phage-based peptide library and have amplified a 123 b oligonucleotide containing a 90 b randomized sequence using PCR. When we run the product in a 1% agarose gel we get a "fuzzy" band, in the 200-300 bp range. Is this normal? I thought that it might be due to the heterogeneity of the product. Thanks. Alan Escher