APOL4   protein_coding

CYP2C8  protein_coding

NAALADL2    protein_coding

NANOS3  protein_coding

C20orf204   protein_coding

MIR429  miRNA

MIR200A miRNA

MIR200B miRNA

I have a file named "gene.txt", which looks like this

GeneName    GeneType

APOL4   protein_coding

CYP2C8  protein_coding

NAALADL2    protein_coding

NANOS3  protein_coding

C20orf204   protein_coding

MIR429  miRNA

MIR200A miRNA

MIR200B miRNA
##</code><code>##

#!/usr/bin/perl -w
use strict;
open FILE1, "/Desktop/gene.txt" or die;
my %hash;
while (my $line=<FILE1>) {

chomp $line;
# print $line,"\n";
(my $word1,my $word2) = split /:/, $line;

$hash{$word1} = $word2;
}
# Print hash for testinf purposes
while ( my ($k,$v) = each %hash ) {
    # print "Key $k  $v\n";
    @keys = keys(%hash);
	print @keys;
}