Hello,

I've been trying to familiarize myself with Bioconductor and have been going through the tutorial in the PDF of "Gene set enrichment with topGO". However, when I enter 

sampleGOdata <- new("topGOdata",
                    description="Simple Session", ontology ="BP",
                    allGenes = geneList, geneSe1 = topDiffGenes,
                    nodeSize=10,
                    annot = annFUN.db, affyLib = affyLib)

I am given the error:

Error in checkAtAssignment("topGOdata", "geneSelectionFun", "NULL") : 
  assignment of an object of class “NULL” is not valid for @‘geneSelectionFun’ in an object of class “topGOdata”; is(value, "function") is not TRUE
In addition: Warning message:
In .local(.Object, ...) :
  No function to select the significant genes provided!

Has anyone encountered a similar problem or know how to go about fixing this? Any recommendations would be greatly appreciated!

Thank you! 

You have a typo. The argument is geneSel, with a lower case L, not geneSe1, with a one.