diff --git a/basenji/genedata.py b/basenji/genedata.py
index d0f37d76..0a7391ce 100755
--- a/basenji/genedata.py
+++ b/basenji/genedata.py
@@ -163,7 +163,7 @@ def subset_genes(self, gene_ids):
         # transcript_map will point to the wrong sequences
 
     def gene_ids(self):
-        return list(self.gene_tss().keys())
+        return list(self.gene_tss.keys())
 
 
     def tss_ids(self):