diff --git a/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/MergeAlleles.scala b/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/MergeAlleles.scala
index ea22e61d276012a64d87f7c24f9a02282b3bf8ca..8a4140d1c51b6ff1a8b0aa2de632b9c87fc48215 100644
--- a/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/MergeAlleles.scala
+++ b/biopet-framework/src/main/scala/nl/lumc/sasc/biopet/tools/MergeAlleles.scala
@@ -15,7 +15,7 @@ import scala.collection.SortedMap
 import scala.collection.mutable.{ Map, Set }
 import nl.lumc.sasc.biopet.core.config.Configurable
 import scala.collection.JavaConversions._
-import org.broadinstitute.gatk.utils.commandline.{ Input, Output, Argument }
+import org.broadinstitute.gatk.utils.commandline.{ Input, Output }
 
 class MergeAlleles(val root: Configurable) extends BiopetJavaCommandLineFunction {
   javaMainClass = getClass.getName
@@ -23,12 +23,14 @@ class MergeAlleles(val root: Configurable) extends BiopetJavaCommandLineFunction
   @Input(doc = "Input vcf files", shortName = "input", required = true)
   var input: List[File] = Nil
 
-  @Output(doc = "Output fastq files", shortName = "output", required = true)
+  @Output(doc = "Output vcf file", shortName = "output", required = true)
   var output: File = _
 
-  @Argument
   var reference: File = config("reference")
 
+  override val defaultVmem = "8G"
+  memoryLimit = Option(4)
+
   override def commandLine = super.commandLine +
     repeat("-I", input) +
     required("-o", output) +