13.1.6 Degenerate Primer Design

A degenerate primer contains a mix of bases at one or more sites. They are useful when you only have the protein sequence of your gene of interest so want to allow for the degeneracy in the genetic code, or when you want to isolate similar genes from a variety of species where the primer binding sites may not be identical. You can design degenerate primers by using either a sequence containing ambiguous bases or an alignment as the template and checking the Allow degeneracy box. The degeneracy value that you specify is the maximum number of primers that any primer sequence is allowed to represent. For example, a primer which contains the nucleotide character N once (and no other ambiguities) has a degeneracy of 4 because N represents the four bases A,C,G and T. A primer that contains an N and an R has degeneracy 4 × 2 = 8 because R represents the two bases A and G.