Basis of differentiation 

Primers 

Promoters 

Definition 

Primers commercially synthesized short DNA sequences used to amplify target DNA sequences in polymerase chain reaction (PCR). 

Promoters are specific regulatory DNA sequences that are found upstream of the transcription initiation site of a site. They provide a secure initial binding site for RNA polymerase and transcription factors to facilitate transcription. 

Length 

Primers have about 20 base pairs. 

Promoters can have about 100-1000 base pairs. 

Function 

Primers serve as starting sequences for the synthesis of a new strand. 

Promoters regulate gene transcription by providing binding sites for RNA polymerase and other transcription factors. They define the direction of the transcriptions and indicate the sense strand of a gene.

Types

2 types

• Forward primers

• Reverse primers

3 types

• Core promoters

• Proximal promoters

• Distal promoters

Sequence 

Primers have nucleotide sequences that are complementary to the flanking ends of the DNA double-strand (target)

Promoters have specific DNA sequences