+my %merge_rsids;
+if (defined $options{merge}) {
+ my $merge = open_compressed_file($options{merge})
+ or die "Unable to open file $options{merge}: $!";
+ while (<$merge>) {
+ chomp;
+ my ($old,$new,undef) = split /\t/;
+ next unless exists $rsids{'rs'.$old};
+ $merge_rsids{'rs'.$old} = 'rs'.$new;
+ $rsids{'rs'.$new} = 1;
+ }
+ close ($merge);
+}
+