diff --git a/modules/seq/base/src/alignment_handle.hh b/modules/seq/base/src/alignment_handle.hh
index 8c66888f1e7d53c3ffede857c24193987677a0f2..bcba027d92f718fb0d874e96361dfc4f0387ffbd 100644
--- a/modules/seq/base/src/alignment_handle.hh
+++ b/modules/seq/base/src/alignment_handle.hh
@@ -157,6 +157,8 @@ public:
   /// \brief Column iterator end-point
   iterator end() const;
 
+  bool IsValid() const { return impl_.get()!=0; }
+  
 private:
   void CheckValidity() const;
   impl::SequenceListImplPtr impl_;