my ($key, $val) = split /\t/, $line;
    push @{ $hash2{$key} }, $val;

##</code><code>##

$VAR1 = {
          '211560_s_at' => [
                             'P'
                           ],
          '204332_s_at' => [
                             'P'
                           ],
          '216064_s_at' => [
                             'P'
                           ],
          '200005_at' => [
                           'P'
                         ],
          '211110_s_at' => [
                             'P'
                           ],
          '200003_s_at' => [
                             'P'
                           ]
        };