diff --git a/mapping/src/main/scala/nl/lumc/sasc/biopet/pipelines/mapping/Mapping.scala b/mapping/src/main/scala/nl/lumc/sasc/biopet/pipelines/mapping/Mapping.scala
index 838de935f7cf45c4da3f9f0af6568f4fc527fbcf..912027fcd5dfdf1acd3203b25ac7c22d685658a2 100644
--- a/mapping/src/main/scala/nl/lumc/sasc/biopet/pipelines/mapping/Mapping.scala
+++ b/mapping/src/main/scala/nl/lumc/sasc/biopet/pipelines/mapping/Mapping.scala
@@ -125,7 +125,7 @@ class Mapping(val root: Configurable) extends QScript with SummaryQScript with S
     "skip_markduplicates" -> skipMarkduplicates,
     "aligner" -> aligner,
     "chunking" -> chunking,
-    "numberChunks" -> (if (chunking) numberChunks.getOrElse(1) else None)
+    "number_of_chunks" -> (if (chunking) numberChunks.getOrElse(1) else None)
   ) ++ (if (root == null) Map("reference" -> referenceSummary) else Map())
 
   override def reportClass = {