public int findPosition(int i);
/**
+ * Returns the from-to sequence positions (start..) for the given column
+ * positions (1..), or null if no residues are included in the range
+ *
+ * @param fromColum
+ * @param toColumn
+ * @return
+ */
+ public Range findPositions(int fromColum, int toColumn);
+
+ /**
* Returns an int array where indices correspond to each residue in the
* sequence and the element value gives its position in the alignment
*