diff --git a/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/Freebayes.scala b/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/Freebayes.scala
index 70c12759257d34434c089b05c3f04176109a104f..059785332d319e47d016f7ea75487aeab4fdeab3 100644
--- a/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/Freebayes.scala
+++ b/public/biopet-extensions/src/main/scala/nl/lumc/sasc/biopet/extensions/Freebayes.scala
@@ -81,7 +81,7 @@ class Freebayes(val root: Configurable) extends BiopetCommandLineFunction with R
   var read_max_mismatch_fraction: Option[Int] = config("read_max_mismatch_fraction")
   var read_snp_limit: Option[Int] = config("read_snp_limit")
   var read_indel_limit: Option[Int] = config("read_indel_limit")
-  var min_alternate_fraction: Option[Int] = config("min_alternate_fraction")
+  var min_alternate_fraction: Option[Double] = config("min_alternate_fraction")
   var min_alternate_count: Option[Int] = config("min_alternate_count")
   var min_alternate_qsum: Option[Int] = config("min_alternate_qsum")
   var min_alternate_total: Option[Int] = config("min_alternate_total")