Hi, I have tried to analyze my scRNA-Seq data set by DESeq2 but as I follow the Recommendations for single-cell analysis,

dds <- DESeq(dds, useT=TRUE, minmu=1e-6, test="LRT",
                      fitType = "glmGamPoi")

I have received this error and couldn't fix it.

Error in DESeq(dds, useT = TRUE, minmu = 1e-06, test = "LRT",  : 
  likelihood ratio test requires a 'reduced' design, see ?DESeq

I would appreciate it if someone could help me.

Would you mind reading the vignette towards how the LRT works: http://bioconductor.org/packages/devel/bioc/vignettes/DESeq2/inst/doc/DESeq2.html#likelihood-ratio-test