It's not a concatination problem, it's an array greediness problem. That is, saying:

..will leave @bar empty -- and rightfully so, as perl has no way of knowing which values were destined for which array. This is much the same problem that you're running into. See the answer at perlfaq.com for the canonical way to fix this.

Update: Bah, I thought at first glance that perlfaq actually gave a snippet of working example code, but they don't. So here's one way to do it:

$one = "YAR033W";
$two = "YAR033W";
@source = ("ITOCORE");
@exper = ("n/a");
print " ($one)($two)(@source)(@exper) \n";
parsed_pair($one, $two, \@source, \@exper);
# ...

sub parsed_pair {
  my ($one, $two, $source_ref, $exper_ref) = @_;
  print " ($one)($two)(@$source_ref)(@$exper_ref) \n";
  #....
}
[download]

See the pass by reference section of perlsub, and/or perlreftut / perlref.

perl -pe '"I lo*`+$^X$\"$]!$/"=~m%(.*)%s;$_=$1;y^`+*^e v^#$&V"+@( NO CARRIER'