diff --git a/creatur.cabal b/creatur.cabal
--- a/creatur.cabal
+++ b/creatur.cabal
@@ -1,5 +1,5 @@
 Name:              creatur
-Version:           4.1.4
+Version:           4.1.6
 Stability:         experimental
 Synopsis:          Framework for artificial life experiments.
 Description:       A software framework for automating experiments
diff --git a/src/ALife/Creatur/Genetics/BRGCWord8.hs b/src/ALife/Creatur/Genetics/BRGCWord8.hs
--- a/src/ALife/Creatur/Genetics/BRGCWord8.hs
+++ b/src/ALife/Creatur/Genetics/BRGCWord8.hs
@@ -218,7 +218,9 @@
 
 -- | Write a raw sequence of Word8 values to the genome
 putRawWord8s :: [Word8] -> Writer ()
-putRawWord8s = mapM_ putRawWord8
+putRawWord8s ys = do
+  xs <- S.get
+  S.put (xs ++ ys)
 
 -- | Read a raw sequence of Word8 values from the genome
 getRawWord8s :: Int -> Reader (Either [String] [Word8])