diff --git a/src/OpenGene.jl b/src/OpenGene.jl
index 1f1aeec..cbc0ab4 100644
--- a/src/OpenGene.jl
+++ b/src/OpenGene.jl
@@ -8,6 +8,7 @@ module OpenGene
 
 using DataFrames
 
+# make it compatible for different version of Julia
 include("compat.jl")
 
 # all code in Base should have no code dependency on others
diff --git a/src/compat.jl b/src/compat.jl
index 53c5f7f..e70b94f 100644
--- a/src/compat.jl
+++ b/src/compat.jl
@@ -1 +1,3 @@
-import Compat:ASCIIString
\ No newline at end of file
+if isdefined(Base, :ASCIIString)==false && isdefined(Base, :String)
+	const ASCIIString = String
+end
\ No newline at end of file