Marjan,

m means a or c

s means c or g

k means g or t

You can design a primer mix where you can get half of the primer in the solution with an A or C etc.

You can check this website for the codes:

http://www.boekhoff.info/?pid=data&dat=fasta-codes

Best

Ijad

Dear Marjan

Those primers can be called as Degenerate primers which can amplify more then one gene of same family or different family.

@ Liad: Thanks for useful link, is it possible to explain more pricise, How can I get half of primer in the solution with A or C?

For comparing in fasta format for allignment which sequence should we input?I mean for examlpe:K or g/t?

@ Gael Thanks many useful