diff --git a/src/chipster.nf b/src/chipster.nf
index 8cadbd769ab03d6bdc12e8a2c01423d871b176dd..3516d2116f94fc1d225bfd5fa49f270f0928ba23 100644
--- a/src/chipster.nf
+++ b/src/chipster.nf
@@ -75,7 +75,7 @@ Channel
   .set { genome_file } 
 
 Channel
-  .fromPath( params.idxgenome )
+  .fromFilePairs( params.idxgenome, size: -1 )
   .set { genome_idx }
 
 /*