The reason the conditional is coming out as true is that it is not parsed the way you think it is:

if ( ($key eq 'ID') or 'TITLE' or 'GENE' or 'CYTOBAND'
     or 'LOCUSLINK' or 'CHROMOSOME' or 'SCOUNT')
  # ...
}
[download]

... is the same thing. The strings 'TITLE', etc. are considered true by perl.

(update: ... and everyone beats me and gives better answers. Sigh...)