diff --git a/fasta.cabal b/fasta.cabal
--- a/fasta.cabal
+++ b/fasta.cabal
@@ -10,7 +10,7 @@
 -- PVP summary:      +-+------- breaking API changes
 --                   | | +----- non-breaking API additions
 --                   | | | +--- code changes with no API change
-version:             0.7.2.1
+version:             0.8.0.0
 
 -- A short (one-line) description of the package.
 synopsis:            A simple, mindless parser for fasta files.
diff --git a/src/Data/Fasta/ByteString/Lazy/Translation.hs b/src/Data/Fasta/ByteString/Lazy/Translation.hs
--- a/src/Data/Fasta/ByteString/Lazy/Translation.hs
+++ b/src/Data/Fasta/ByteString/Lazy/Translation.hs
@@ -29,8 +29,8 @@
                    | otherwise    -> a : go b
 
 -- | Converts a codon to an amino acid
--- Remember, if there is an "N" in that DNA sequence, then it is invalid
--- and treated as a gap
+-- Remember, if there is an "N" in that DNA sequence, then it is translated
+-- as an X, an unknown amino acid.
 codon2aa :: Codon -> Either BL.ByteString BL.ByteString
 codon2aa x
     | codon `elem` ["GCT", "GCC", "GCA", "GCG"]               = Right "A"
@@ -56,7 +56,7 @@
     | codon `elem` ["TAA", "TGA", "TAG"]                      = Right "*"
     | codon `elem` ["---", "..."]                             = Right "-"
     | codon == "~~~"                                          = Right "-"
-    | 'N' `BL.elem` codon                                     = Right "-"
+    | 'N' `BL.elem` codon                                     = Right "X"
     | '-' `BL.elem` codon                                     = Right "-"
     | '.' `BL.elem` codon                                     = Right "-"
     | otherwise                                               = Left errorMsg
diff --git a/src/Data/Fasta/ByteString/Translation.hs b/src/Data/Fasta/ByteString/Translation.hs
--- a/src/Data/Fasta/ByteString/Translation.hs
+++ b/src/Data/Fasta/ByteString/Translation.hs
@@ -28,8 +28,8 @@
                    | otherwise    -> a : go b
 
 -- | Converts a codon to an amino acid
--- Remember, if there is an "N" in that DNA sequence, then it is invalid
--- and treated as a gap
+-- Remember, if there is an "N" in that DNA sequence, then it is translated
+-- as an X, an unknown amino acid.
 codon2aa :: Codon -> Either B.ByteString B.ByteString
 codon2aa x
     | codon `elem` ["GCT", "GCC", "GCA", "GCG"]               = Right "A"
@@ -55,7 +55,7 @@
     | codon `elem` ["TAA", "TGA", "TAG"]                      = Right "*"
     | codon `elem` ["---", "..."]                             = Right "-"
     | codon == "~~~"                                          = Right "-"
-    | "N" `B.isInfixOf` codon                                 = Right "-"
+    | "N" `B.isInfixOf` codon                                 = Right "X"
     | "-" `B.isInfixOf` codon                                 = Right "-"
     | "." `B.isInfixOf` codon                                 = Right "-"
     | otherwise                                               = Left errorMsg
diff --git a/src/Data/Fasta/String/Translation.hs b/src/Data/Fasta/String/Translation.hs
--- a/src/Data/Fasta/String/Translation.hs
+++ b/src/Data/Fasta/String/Translation.hs
@@ -18,8 +18,8 @@
 import Data.Fasta.String.Types
 
 -- | Converts a codon to an amino acid
--- Remember, if there is an "N" in that DNA sequence, then it is invalid
--- and treated as a gap
+-- Remember, if there is an "N" in that DNA sequence, then it is translated
+-- as an X, an unknown amino acid.
 codon2aa :: Codon -> Either String Char
 codon2aa x
     | codon `elem` ["GCT", "GCC", "GCA", "GCG"]               = Right 'A'
@@ -45,7 +45,7 @@
     | codon `elem` ["TAA", "TGA", "TAG"]                      = Right '*'
     | codon `elem` ["---", "..."]                             = Right '-'
     | codon == "~~~"                                          = Right '-'
-    | 'N' `elem` codon                                        = Right '-'
+    | 'N' `elem` codon                                        = Right 'X'
     | '-' `elem` codon                                        = Right '-'
     | '.' `elem` codon                                        = Right '-'
     | otherwise                                               = Left errorMsg
diff --git a/src/Data/Fasta/Text/Lazy/Translation.hs b/src/Data/Fasta/Text/Lazy/Translation.hs
--- a/src/Data/Fasta/Text/Lazy/Translation.hs
+++ b/src/Data/Fasta/Text/Lazy/Translation.hs
@@ -19,8 +19,8 @@
 import Data.Fasta.Text.Lazy.Types
 
 -- | Converts a codon to an amino acid
--- Remember, if there is an "N" in that DNA sequence, then it is invalid
--- and treated as a gap
+-- Remember, if there is an "N" in that DNA sequence, then it is translated
+-- as an X, an unknown amino acid.
 codon2aa :: Codon -> Either T.Text T.Text
 codon2aa x
     | codon `elem` ["GCT", "GCC", "GCA", "GCG"]               = Right "A"
@@ -46,7 +46,7 @@
     | codon `elem` ["TAA", "TGA", "TAG"]                      = Right "*"
     | codon `elem` ["---", "..."]                             = Right "-"
     | codon == "~~~"                                          = Right "-"
-    | "N" `T.isInfixOf` codon                                 = Right "-"
+    | "N" `T.isInfixOf` codon                                 = Right "X"
     | "-" `T.isInfixOf` codon                                 = Right "-"
     | "." `T.isInfixOf` codon                                 = Right "-"
     | otherwise                                               = Left errorMsg
diff --git a/src/Data/Fasta/Text/Translation.hs b/src/Data/Fasta/Text/Translation.hs
--- a/src/Data/Fasta/Text/Translation.hs
+++ b/src/Data/Fasta/Text/Translation.hs
@@ -18,8 +18,8 @@
 import Data.Fasta.Text.Types
 
 -- | Converts a codon to an amino acid
--- Remember, if there is an "N" in that DNA sequence, then it is invalid
--- and treated as a gap
+-- Remember, if there is an "N" in that DNA sequence, then it is translated
+-- as an X, an unknown amino acid.
 codon2aa :: Codon -> Either T.Text T.Text
 codon2aa x
     | codon `elem` ["GCT", "GCC", "GCA", "GCG"]               = Right "A"
@@ -45,7 +45,7 @@
     | codon `elem` ["TAA", "TGA", "TAG"]                      = Right "*"
     | codon `elem` ["---", "..."]                             = Right "-"
     | codon == "~~~"                                          = Right "-"
-    | "N" `T.isInfixOf` codon                                 = Right "-"
+    | "N" `T.isInfixOf` codon                                 = Right "X"
     | "-" `T.isInfixOf` codon                                 = Right "-"
     | "." `T.isInfixOf` codon                                 = Right "-"
     | otherwise                                               = Left errorMsg