This feature allows to search for primer pairs that span corresponding introns on the genomic sequence or exon junctions on the mRNA sequence.
Note that this feature that RT-PCR design is only available for mRNA/cDNA sequences with annotated exons. There are several ways to obtain the cDNA for a corresponding DNA sequence.
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This option makes sure that each detected primer pair product should span an intron in on the genomic sequence i.e the forward and reverse primers must be located in different exons. The option is enabled by default.
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