Hi

The important section of the oligos sequence for your gene of interest is usually approximately in the first 20 amino acids of the 5 'region. In this case, if your initial sequence of those 20 amino acids in the 5´-3´ direction is correct, I do not think there is a major problem, since it is possible that the fragment of your oligo is sufficient for successful recognition.

Should be ok, you could do a check on Primer-Blast to see if there is any other potential non-specific binding

A 21 bp primer should be long enough to still be specific to your gene of interest, as others said, BLAST it for specificity. Shortening a primer might change it's annealing temp, you might want to try a gradient PCR to be sure.

Out of curiosity, why did you shorten your primer?

Thanks, everyone.The primers worked.

Katie A Burnette - I made a blunder while ordering the primers.