diff --git a/wGRR b/wGRR
index 1172eb4674256b164fd1572b6ff55a6b49906298..8f2d006d9fb39bd83517673c61ab101723158262 100755
--- a/wGRR
+++ b/wGRR
@@ -266,7 +266,7 @@ if [[ -f $OUT.allpairs.txt ]] ; then
 else
 	printf "%-10s  --  %s\n" "[INFO]" "Writing genomes pairs"
 	printf "%-10s  --  %s\n" "[TIME]" $(textifyDuration $duration)
-	$AWKEXE '/^>/{g=substr($1,2);gsub(/_[0-9]+$/,"",g);a[g]++}END{for(i in a){for(j in a){if(i != j && !(j" "i in b)){print i"\t"j;b[i" "j]++}}}}' $PRT > $OUT.allpairs.txt
+	$AWKEXE 'BEGIN{x=1}/^>/{g=substr($1,2);gsub(/_[0-9]+$/,"",g);if(FNR==1){a[x]=g;++x;currg=g;next}if(g!=currg){a[x]=g;x++;currg=g}}END{i=0;while(++i in a){j=i;while(++j in a){print a[i]"\t"a[j]}}}' $PRT > $OUT.allpairs.txt
 	printf "%-10s  --  %s\n" "[INFO]" "$(wc -l $OUT.allpairs.txt | awk '{print $1}') pairs written"
 fi