diff --git a/mrdna/segmentmodel.py b/mrdna/segmentmodel.py
index bebf3c72a2500bdaf2f174279c89889951b46ec1..ceb19ebc03d234556075b775d55415c48b18864f 100644
--- a/mrdna/segmentmodel.py
+++ b/mrdna/segmentmodel.py
@@ -744,8 +744,13 @@ class Segment(ConnectableElement, Group):
     ## TODO? Replace with abstract strand-based model?
 
     def add_nick(self, nt, on_fwd_strand=True):
-        self.add_3prime(nt,on_fwd_strand)
-        self.add_5prime(nt+1,on_fwd_strand)
+        if on_fwd_strand:
+            self.add_3prime(nt,on_fwd_strand)
+            self.add_5prime(nt+1,on_fwd_strand)
+        else:
+            self.add_5prime(nt,on_fwd_strand)
+            self.add_3prime(nt+1,on_fwd_strand)
+
 
     def add_5prime(self, nt, on_fwd_strand=True):
         if isinstance(self,SingleStrandedSegment):