#! /usr/bin/perl -w
use strict;

my @genes;
my $screen = "ATCGATCGXXXXXATCGATXXXACTGCTACGGTACXXXAATTATXGCGCGXXT";

if ($screen =~ /X/) {

    @genes = split /X+/, $screen;
    my $genecounter = @genes;
    print "Number of components  = $genecounter\n\n";

}