How do I create or import a single-stranded DNA sequence?
SnapGene 5.2 and later allow creation, import, and manipulation of single-stranded DNA (ssDNA) sequences.
Create a New Single-Stranded DNA Sequence
Click menu File → New DNA File to open the "New DNA File" dialog.
Type or paste a DNA sequence into the sequence field.
Set the Topology to "Single-Stranded", and select whether the sequence will be linear or circular.
Enter a name for the new sequence and click OK.
Import a Single-Stranded DNA Sequence from NCBI
Click menu File → Import → NCBI Sequences.
Enter the accession number(s) of the sequence(s) of interest, then click Import.
An NCBI GenBank record must have "ss-DNA" in the file LOCUS header to be imported by SnapGene as a single-stranded sequence. Note that not all NCBI records for single-stranded sequences contain the "ss-DNA" term. If a ssDNA sequence imports as dsDNA, you can convert it — see Convert Between Single-Stranded or Double-Stranded Formats.