How do I import RNA files in SnapGene?
SnapGene versions 5.3 and later have a specific RNA file type (extension .rna). Earlier versions of SnapGene will import RNA sequences as DNA.
Import an RNA File from NCBI
The NCBI database stores all RNA sequences as DNA. When SnapGene imports a ss-RNA, RNA or mRNA file it will convert the sequence to RNA (T→U).
Import an RNA file via menu File → Import sequence → Import NCBI sequence.

Enter the Sequence Accession Number

Enter one or more valid NCBI accession numbers for RNA sequences then click Import.

SnapGene will honor NCBI LOCUS information and import RNA files as RNA.

Click File → Save to save the sequence as a SnapGene .rna file.