push( @{ $gene_hash{$gene_key}{min_start} }, $start ); 
    push( @{ $gene_hash{$gene_key}{max_end} },   $end ); 
    push( @{ $gene_hash{$gene_key}{max_ex} },    $ex ); 

##</code><code>##

   my $Low=min( @ {$gene_hash{$key}{min_start} } );   
   my $High=max( @ {$gene_hash{$key}{max_end} } );
   my $High_ex=max( @ {$gene_hash{$key}{max_ex} } );

##</code><code>##

while (<DATA>) {
    chomp;
    my ($chr, $start, $end, $gene, $ex) = split(/\t/, $_);
    my $gene_key = $chr.":".$gene;
    my $cur_gene = $gene_hash{$gene_key};
    $$cur_gene{min_start} = $start unless $$cur_gene{min_start}<$start;
    $$cur_gene{max_end} = $end unless $$cur_gene{max_end}>$end;
    $$cur_gene{max_ex} = $ex unless $$cur_gene{max_ex}>$ex;
    $gene_hash{$gene_key} = $cur_gene;
}

##</code><code>##

   my $Low=$gene_hash{$key}{min_start};   
   my $High=$gene_hash{$key}{max_end};
   my $High_ex=$gene_hash{$key}{max_ex};