diff --git a/mutalyzer/describe.py b/mutalyzer/describe.py
index b27c037d367e92bde31bbc8b890988421293f5af..f722db01eea6dbc29d876cfa02fbe4de40076a41 100644
--- a/mutalyzer/describe.py
+++ b/mutalyzer/describe.py
@@ -173,6 +173,10 @@ class Seq(object):
         self.start = start
         self.end = end
         self.reverse = reverse
+
+        self.type = "trans"
+        if self.sequence:
+            self.type = "ins"
     #__init__
 
     def __str__(self):