diff --git a/course_files/de-real.Rmd b/course_files/de-real.Rmd
index 3a07166abc14b96bb269ac877d41009a3c30e212..6429f1492771297232af5a628401eae1561662e2 100644
--- a/course_files/de-real.Rmd
+++ b/course_files/de-real.Rmd
@@ -208,7 +208,7 @@ The first steps for this analysis then involve
 keep_gene <- (rowSums(counts_mat > 0) > 29.5 & rowMeans(counts_mat) > 0.2)
 table(keep_gene)
 dge <- DGEList(
-    counts_mat = counts_mat[keep_gene,], 
+    counts = counts_mat[keep_gene,], 
     norm.factors = rep(1, length(counts_mat[1,])), 
     group = group
 )