diff --git a/python/obitools3/dms/obiseq.pyx b/python/obitools3/dms/obiseq.pyx
index 20ac4d2..5ee1d89 100644
--- a/python/obitools3/dms/obiseq.pyx
+++ b/python/obitools3/dms/obiseq.pyx
@@ -21,7 +21,7 @@ cdef class Seq(dict) :
         if tags is not None :
             for k in tags:
                 k_b = tobytes(k)
-                self[k_b] = tags[k_b]
+                self[k_b] = tags[k]
 
 
     def __contains__(self, object key):
@@ -70,11 +70,10 @@ cdef class Nuc_Seq(Seq) :
     # nuc sequence property getter and setter
     @property
     def seq(self):
-        return self._seq
+        return self[NUC_SEQUENCE_COLUMN]
     
     @seq.setter
     def seq(self, object new_seq):  # @DuplicatedSignature
-        self._seq = new_seq
         self[NUC_SEQUENCE_COLUMN] = tobytes(new_seq)
         
     # sequence quality property getter and setter