Thank you *all* for your help and insights. Reading through your comments and code critiques (and the article link) was just what I needed tonight. I tightened up my code per your suggestions, changed:

if ($Gene_Symbol =~ /Hox/) {
[download]

to

if ($symbols{$key} =~ /^Hox/) {
[download]

and it worked like a charm. Now I not only have a script that works, but I also learned a few new approaches to try as well. (I am working with very large datasets, so I think I'll stick with five hashes.) Thanks again wise monks!! -- TempAcolyte