anchor.diff:  (defgeneric transcripts (ens-obj)
     (:documentation "Return a list of all transcripts corresponding to
   the object, or nil if no such transcript exists.
  -Example:
  +
  +###Example:
   * (transcripts (sample_gene_tp53))
   
   (#<TRANSCRIPT {100293BCE1}> #<TRANSCRIPT {100293CF61}>
  
positive.code: 
  (defparameter *coordinate-systems* (select 'coord-system :flatp t))
  
  (defparameter *tp53* nil)
  
  (defun sample_gene_tp53 () 
    "The gene tp53 is retrieved from Ensembl and stored in the parameter *tp53*. If that parameter is already set, then it will be returned directly. The 'Tumour Protein 53' is one of the better-studied proteins and most biologists will immediately know its properties. This shall contribute to making the examples better understood.
  Example:
  * (SAMPLE_GENE_TP53)
  
  Gene TP53 successfully retrieved from Ensembl.
  #<GENE {10027FDC21}>
  * (SAMPLE_GENE_TP53)
  
  #<GENE {10027FDC21}>
    "
    (if *tp53* *tp53*
       (progn (if (setf *tp53* (fetch-by-stable-id "ENSG00000141510"))
  		 (print "Gene TP53 successfully retrieved from Ensembl.")
  		 (print "Gene TP53 could not be retrieved."))
  	     *tp53*)))
  
  
  ;;; fetch objects from the MySQL database
  
negative.code:     (transmembrane-protein-p (translation ts))))
  
  (defun codes-tm-protein (gene)
    "True iff at least one transcript of that genes codes for a
  transmembrane protein."
    (some #'transmembrane-protein-p (slot-value gene 'transcript)))
  
  (defun codes-non-tm-protein (gene)
  