--- a/src/Bio/Core/Sequence.hs
+++ b/src/Bio/Core/Sequence.hs
@@ -37,2 +37,3 @@ import Data.Stringable hiding (length)
 import Data.Monoid
+import qualified Data.Semigroup as S
 
@@ -42,2 +43,5 @@ newtype SeqData  = SeqData { unSD :: LC.ByteString }
 
+instance S.Semigroup SeqData where
+  (<>) (SeqData s1) (SeqData s2) = SeqData (mappend s1 s2)
+
 instance Monoid SeqData where
@@ -51,2 +55,9 @@ newtype SeqLabel = SeqLabel { unSL :: LC.ByteString }
 
+instance S.Semigroup SeqLabel where
+  (<>) (SeqLabel s1) (SeqLabel s2) = let
+    (i1:r1) = LC.words s1
+    (i2:r2) = LC.words s2
+    sid = mconcat [i1,(LC.pack ":"),i2]
+    in SeqLabel (LC.unwords ([sid]++r1++[LC.pack ":"]++r2))
+
 instance Monoid SeqLabel where
@@ -68,2 +79,5 @@ newtype QualData = QualData { unQD :: L.ByteString }
 
+instance S.Semigroup QualData where
+  (<>) (QualData s1) (QualData s2) = QualData (mappend s1 s2)
+
 instance Monoid QualData where