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;
}