$db_query = "SELECT ST.sno_name,HT.homolog_name FROM sno_Table ST,Homolog_Table HT,sno_Homologs SH,Organism O 
WHERE ST.sno_id=SH.sno_id AND SH.homolog_id=HT.homolog_id AND HT.org_id=O.org_id and (ST.family=$family) and
O.organism='$TB'";
	print "db_query: $db_query<br>"; # add this
	my $sth = $dbh->prepare($db_query);
	$sth->execute();
	my $total = $sth->rows;
	print "total rows: $total<br>"; # add this