my $sfa =
    $registry->get_adaptor( 'Human', 'Core', 'SupportingFeature' );

  my @supporting_feats = @{ $sfa->fetch_all_by_Exon($exon) };

  my ( $self, $exon )  = @_;

  my $out = [];

  unless($exon->dbID) {
    warning("Cannot retrieve evidence for exon without dbID");
    return [];
  }

  my $sth = $self->prepare("SELECT sf.feature_type, sf.feature_id
                            FROM   supporting_feature sf
                            WHERE  exon_id = ?");

  $sth->bind_param(1,$exon->dbID,SQL_INTEGER);
  $sth->execute();

  my $prot_adp = $self->db->get_ProteinAlignFeatureAdaptor;
  my $dna_adp  = $self->db->get_DnaAlignFeatureAdaptor;

  my $feature;
  while(my ($type, $feature_id) = $sth->fetchrow){
    if($type eq 'protein_align_feature'){
      $feature = $prot_adp->fetch_by_dbID($feature_id);
    } elsif($type eq 'dna_align_feature'){
      $feature = $dna_adp->fetch_by_dbID($feature_id);
    } else {
      warning("Unknown feature type [$type]\n");
    }

    if(!$feature) {
      warning("Supporting feature $type $feature_id does not exist in DB");
    } else {
      my $new_feature = $feature->transfer($exon->slice());
      push @$out, $new_feature if( $new_feature );
    }
  }

  $sth->finish();

  return $out;

  my ( $self, $exon_dbID, $aln_objs ) = @_;

  my $pep_check_sql = 
      "SELECT protein_align_feature_id " . 
      "FROM protein_align_feature " . 
      "WHERE seq_region_id = ? " . 
      "AND   seq_region_start = ? " . 
      "AND   seq_region_end   = ? " .
      "AND   seq_region_strand = ? " . 
      "AND   hit_name = ? " . 
      "AND   hit_start = ? " . 
      "AND   hit_end   = ? " . 
      "AND   analysis_id = ? " . 
      "AND   cigar_line = ? ";

  my $dna_check_sql = 
      "SELECT dna_align_feature_id " . 
      "FROM dna_align_feature " . 
      "WHERE seq_region_id = ? " . 
      "AND   seq_region_start = ? " . 
      "AND   seq_region_end   = ? " .
      "AND   seq_region_strand = ? " . 
      "AND   hit_name = ? " . 
      "AND   hit_start = ? " . 
      "AND   hit_end   = ? " . 
      "AND   analysis_id = ? " . 
      "AND   cigar_line = ? " . 
      "AND   hit_strand = ? ";

  my $assoc_check_sql = 
      "SELECT * " .  
      "FROM  supporting_feature " . 
      "WHERE exon_id = $exon_dbID " . 
      "AND   feature_type = ? " . 
      "AND   feature_id   = ? ";

  my $assoc_write_sql = "INSERT into supporting_feature " . 
      "(exon_id, feature_id, feature_type) " . 
      "values(?, ?, ?)";

  my $pep_check_sth = $self->prepare($pep_check_sql);
  my $dna_check_sth = $self->prepare($dna_check_sql);
  my $assoc_check_sth = $self->prepare($assoc_check_sql);
  my $sf_sth = $self->prepare($assoc_write_sql);

  my $dna_adaptor = $self->db->get_DnaAlignFeatureAdaptor();
  my $pep_adaptor = $self->db->get_ProteinAlignFeatureAdaptor();

  foreach my $f (@$aln_objs) {
    # check that the feature is in toplevel coords

    if($f->slice->start != 1 || $f->slice->strand != 1) {
    #move feature onto a slice of the entire seq_region
      my $tls = $self->db->get_sliceAdaptor->fetch_by_region($f->slice->coord_system->name(),
                                                             $f->slice->seq_region_name(),
                                                             undef, #start
                                                             undef, #end
                                                             undef, #strand
                                                             $f->slice->coord_system->version());
      $f = $f->transfer($tls);

      if(!$f) {
        throw('Could not transfer Feature to slice of ' .
              'entire seq_region prior to storing');
      }
    }

    if(!$f->isa("Bio::EnsEMBL::BaseAlignFeature")){
      throw("$f must be an align feature otherwise" .
            "it can't be stored");
    }
    
    my ($sf_dbID, $type, $adap, $check_sth);
    
    my @check_args = ($self->db->get_SliceAdaptor->get_seq_region_id($f->slice),
                      $f->start,
                      $f->end,
                      $f->strand,
                      $f->hseqname,
                      $f->hstart,
                      $f->hend,
                      $f->analysis->dbID,
                      $f->cigar_string);

    if($f->isa("Bio::EnsEMBL::DnaDnaAlignFeature")){
      $adap = $dna_adaptor;      
      $check_sth = $dna_check_sth;
      $type = 'dna_align_feature';
      push @check_args, $f->hstrand;
    } elsif($f->isa("Bio::EnsEMBL::DnaPepAlignFeature")){
      $adap = $pep_adaptor;
      $check_sth = $pep_check_sth;
      $type = 'protein_align_feature';
    } else {
      warning("Supporting feature of unknown type. Skipping : [$f]\n");
      next;
    }

    $check_sth->execute(@check_args);
    $sf_dbID = $check_sth->fetchrow_array;
    if (not $sf_dbID) {
      $adap->store($f);
      $sf_dbID = $f->dbID;
    }

    # now check association
    $assoc_check_sth->execute($type,
                              $sf_dbID);
    if (not $assoc_check_sth->fetchrow_array) {    
      $sf_sth->bind_param(1, $exon_dbID, SQL_INTEGER);
      $sf_sth->bind_param(2, $sf_dbID, SQL_INTEGER);
      $sf_sth->bind_param(3, $type, SQL_VARCHAR);
      $sf_sth->execute();
    }
  }

  $dna_check_sth->finish;
  $pep_check_sth->finish;
  $assoc_check_sth->finish;
  $sf_sth->finish;
  
}



1;

  Copyright (c) 1999-2009 The European Bioinformatics Institute and
  Genome Research Limited.  All rights reserved.

  This software is distributed under a modified Apache license.
  For license details, please see

    /info/about/code_licence.html

  Please email comments or questions to the public Ensembl
  developers list at <ensembl-dev@ebi.ac.uk>.

  Questions may also be sent to the Ensembl help desk at
  <helpdesk@ensembl.org>.