diff --git a/pdistancer.py b/pdistancer.py
index 708cda1..af2a861 100644
--- a/pdistancer.py
+++ b/pdistancer.py
@@ -71,6 +71,9 @@ def average(list):
         elif speciesname == species1 != species2:
             interperspecies.append(pdist)
             neighbors.update({species2: [pdist]})
+        elif speciesname == species2 != species1:
+            interperspecies.append(pdist)
+            neighbors.update({species2: [pdist]})
     d_max = 'N/A'
     dmin_nn = 'N/A'
     nearestneighbor = 'N/A'