the terms forwards and reverse are arbitrary in pcr and often used just to distinguish the two primers. In sanger sequencing there is no readable sequence under the sequencing primer or for the next 30 bases from each sequencing primer so when you read a sequence the only primer sequence is the reverse complement of the other primer at the far end of the sequence from the sequencing primer

Hi there,

How long are your sequences? If each sequence (forward and reverse) is not very long it may have happened that the Sanger sequenced all your fragment and went on sequencing also the reverse primer. This would be the case if both your forward and reverse sequencing are almost the same length.

The reason you don't see the forward primer in the forward sequence may be that often Sanger sequences are a bit confused in the beginning of the nucleotide sequence (for about 20/30bp) and that's exactly where your primer should be.

Hope this helps!

the terms forwards and reverse are arbitrary in pcr and often used just to distinguish the two primers. In sanger sequencing there is no readable sequence under the sequencing primer or for the next 30 bases from each sequencing primer so when you read a sequence the only primer sequence is the reverse complement of the other primer at the far end of the sequence from the sequencing primer

• Agree with Paul
• And remeber your primers are COMPLIMENTARY to the actual strands you sequence and you revererse complement your target sequence for the reverse primer to generate the actual primer sequence
• Ultimately though, as Paul mentioned it doesnt reallymatter:, i.e. names are just conventions As long as you can align the two sequences and as long as they BLAST to your target/gene of interest that is all that matters

Francesco Martoni yes, my sequences are shorter than 250 bp

Paul Rutland , Laurence Stuart Dawkins-Hall Oh I got it now, thanks a lot for your brief and clear answer