Hello

I have been attempting to perform genome searching using the vignette:  Efficient genome searching with Biostrings and the BSgenome data packages.  

I do not receive an error when follow the vignette using the C elegans genome that is used in the example .  When change the genome to D rerio and include a single DNA sequence (as an XStringviews) to search I get the following:

Error in normargPattern(pattern, subject) : 
'pattern' must be a single string or an XString object

from normargPattern (Biostrings) ciring

else if (!isSingleString(pattern)) 
stop("'", argname, "' must be a single string or an XString object")

when I test the isSingleString function, the response is TRUE.

Any suggestion on how to get past this?