my @data = do {
  open(my $fh, '<', 'yourfile') or die("ack: $!");
  local $/ = '>gb|';
  scalar <$fh>;      # first read will be useless
  <$fh>; 
};
my @nums = qw( 456-3210 4670-5490 );

for my $n (@nums) {
  print map  { '>gb|' . substr($_, 0, -4) }
        grep { $_ =~ /^$n/ } @data;
}