#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

use List::Util qw{ sum };

<DATA>;  # ignore the first line;
say "GeneID\tSum";

while (<DATA>) {
    my @cols = split ' ';
    my $sum = sum(@cols[1 .. $#cols]);
    say join "\t", $cols[0], $sum;
}