tie my %seqindex, "BerkeleyDB::Hash",
           -Filename => $globals{seq_xref},
           -Flags    => DB_RDONLY
  or goto bail;

tie my %alt_seqindex, 'Hash::Case::Preserve';
foreach my $key (keys %seqindex){
  $alt_seqindex{$key} = $seqindex{$key};
};