#open 2 data files
if (open(DNAInputFile01, 'DNA_seq01.txt')) {
	print "File DNA_seq01.txt opened OK \n";
}
else {
	print "Cannot open file DNA_seq01.txt\n";
	exit;
}

if (open(DNAInputFile02, 'DNA_seq02.txt')) {
	print "File DNA_seq02.txt opened OK \n";
}
else {
	print "Cannot open file DNA_seq02.txt\n";
	exit;
}

#read from file, store as array  @ for array variable
$line1 = <DNAInputFile01>;
close DNAInputFile01;  #close the input file
$line2 = <DNAInputFile02>;
close DNAInputFile02;  #close the input file

print "file 1: ",$line1,"\n";
print "file 2: ",$line2,"\n";

$combineline = $line1.$line2;
print "combined line: ",$combineline,"\n";

print "Here is the result of transcribing the DNA to RNA (T to U): \n";
$combineline =~ s/T/U/g;  
print "$combineline\n";

exit;