diff --git a/annot.nf b/annot.nf
index a643529..d2c80e2 100644
--- a/annot.nf
+++ b/annot.nf
@@ -107,7 +107,7 @@ if (params.do_contiguation) {
         file 'pseudo.contigs.fasta' into contigs_seq
         // TODO If upgrading to DSL2, can just use json output and splitJson operator before circos_run_chrs process.
         file 'ref_target_mapping.txt' into ref_target_mapping_circos
-        file 'ref_target_mapping.json' into ref_target_mapping_integrate
+        file 'ref_target_mapping.json' into ref_target_mapping
 
         """
         abacas2.nonparallel.sh \
@@ -129,7 +129,7 @@ if (params.do_contiguation) {
         file 'pseudo.scafs.fasta' into scaffolds_seq
         file 'pseudo.scafs.agp' into scaffolds_agp
         file 'pseudo.contigs.fasta' into contigs_seq
-        file 'ref_target_mapping.json' into ref_target_mapping_integrate
+        file 'ref_target_mapping.json' into ref_target_mapping
 
         """
         no_abacas_prepare.lua ${sanitized_genome_file} pseudo
@@ -170,6 +170,9 @@ pseudochr_agp.into{ pseudochr_agp_augustus
 				    pseudochr_agp_make_gaps
                     pseudochr_agp_make_dist }
 
+ref_target_mapping.into{ ref_target_mapping_integrate
+                         ref_target_mapping_pseudo }
+
 // TRNA PREDICTION
 // ===============
 
@@ -886,6 +889,7 @@ if (params.do_pseudo) {
         file 'pseudochr.fasta' from pseudochr_seq_pseudogene_calling
         file 'genes.gff3' from integrated_gff3_clean
         file 'last.out' from pseudochr_last_out.collectFile()
+        file 'ref_target_mapping.json' from ref_target_mapping_pseudo
 
         output:
         file 'genes_and_pseudo.gff3' into gff3_with_pseudogenes
@@ -899,7 +903,8 @@ if (params.do_pseudo) {
         if [ ! -s last_and_genes.gff3 ]; then
           echo '##gff-version 3' > last_and_genes.gff3
         fi
-        pseudo_merge_with_genes.lua last_and_genes.gff3 pseudochr.fasta > out_tmp.gff3
+        pseudo_merge_with_genes.lua last_and_genes.gff3 pseudochr.fasta \
+          -m ref_target_mapping.json -o ${params.MAX_OVERLAP} > out_tmp.gff3
         gt gff3 -sort -retainids -tidy out_tmp.gff3 > genes_and_pseudo.gff3
         """
     }
diff --git a/bin/integrate_gene_calls.lua b/bin/integrate_gene_calls.lua
index b34e97f..1490224 100755
--- a/bin/integrate_gene_calls.lua
+++ b/bin/integrate_gene_calls.lua
@@ -97,26 +97,6 @@ function stream:process_current_cluster()
   end
 end
 
-function stream:conditional_overlap(new_rng)
-  local ext_rng = nil
-
-  if ref_target_mapping then
-    -- allow short overlaps for apicoplasts and mitochondria
-    if (ref_target_mapping.API and self.last_seqid == ref_target_mapping.API[2])
-      or (ref_target_mapping.MIT and self.last_seqid == ref_target_mapping.MIT[2]) then
-      local ext = options.overlap
-      -- ensure consistent start and end bases for new range
-      if self.curr_rng:get_start() < new_rng:get_start() then
-        ext_rng = gt.range_new(math.min(new_rng:get_start() + ext, new_rng:get_end()), new_rng:get_end())
-      else
-        ext_rng = gt.range_new(new_rng:get_start(), math.max(new_rng:get_start(), new_rng:get_end() - ext))
-      end
-      return self.curr_rng:overlap(ext_rng)
-    end
-  end
-  return self.curr_rng:overlap(new_rng)
-end
-
 function stream:next_tree()
   local complete_cluster = false
   local mygn = nil
@@ -141,7 +121,7 @@ function stream:next_tree()
           else
             if self.last_seqid == fn:get_seqid()
                 and self.last_strand == fn:get_strand()
-                and self:conditional_overlap(new_rng) then
+                and conditional_overlap(ref_target_mapping, self.curr_rng, new_rng, self.last_seqid, options.overlap) then
               table.insert(self.curr_gene_set, fn)
               self.curr_rng = self.curr_rng:join(new_rng)
             else
diff --git a/bin/lib.lua b/bin/lib.lua
index 1f6f2b1..b88b4e4 100644
--- a/bin/lib.lua
+++ b/bin/lib.lua
@@ -593,4 +593,24 @@ function infernal_in_stream_new(myio)
     end
   end
   return s
-end
\ No newline at end of file
+end
+
+function conditional_overlap(ref_target_mapping, curr_rng, new_rng, last_seqid, overlap)
+  local ext_rng = nil
+
+  if ref_target_mapping then
+    -- allow short overlaps for apicoplasts and mitochondria
+    if (ref_target_mapping.API and last_seqid == ref_target_mapping.API[2])
+      or (ref_target_mapping.MIT and last_seqid == ref_target_mapping.MIT[2]) then
+      local ext = overlap
+      -- ensure consistent start and end bases for new range
+      if curr_rng:get_start() < new_rng:get_start() then
+        ext_rng = gt.range_new(math.min(new_rng:get_start() + ext, new_rng:get_end()), new_rng:get_end())
+      else
+        ext_rng = gt.range_new(new_rng:get_start(), math.max(new_rng:get_start(), new_rng:get_end() - ext))
+      end
+      return curr_rng:overlap(ext_rng)
+    end
+  end
+  return curr_rng:overlap(new_rng)
+end
diff --git a/bin/pseudo_merge_with_genes.lua b/bin/pseudo_merge_with_genes.lua
index 3dc8d81..7a03337 100755
--- a/bin/pseudo_merge_with_genes.lua
+++ b/bin/pseudo_merge_with_genes.lua
@@ -23,6 +23,7 @@ to_gene = {pseudogene = 'gene', pseudogenic_transcript = 'mRNA',
 package.path = gt.script_dir .. "/?.lua;" .. package.path
 require("lib")
 require("optparse")
+local json = require ("dkjson")
 
 op = OptionParser:new({usage="%prog <options> merged_gff_file.gff3 sequence.fas",
                        oneliner="Adds pseudogene annotations to existing set of gene models.",
@@ -30,7 +31,7 @@ op = OptionParser:new({usage="%prog <options> merged_gff_file.gff3 sequence.fas"
 op:option{"-t", action='store', dest='threshold',
                 help="minimum gene coverage ratio threshold for pseudogene "
                   .. "required to replace a gene (e.g. 0.6 for 60%)"}
-op:option{"-m", action='store', dest='minratio',
+op:option{"-n", action='store', dest='minratio',
                 help="minimal 'stitching' gene coverage ratio "
                   .. "required to replace multiple genes (e.g. 0.8 for 80%)"}
 op:option{"-x", action='store', dest='maxratio',
@@ -44,10 +45,14 @@ op:option{"-r", action='store', dest='rejectfile',
 op:option{"-l", action='store', dest='longest_until',
                 help="pick candidate with median length if at least "
                   .. "<LONGEST_UNTIL> candidates per locus"}
+op:option{"-m", action='store', dest='mapping',
+                help="reference target chromosome mapping"}
+op:option{"-o", action='store', dest='overlap', default=0,
+                help="number of bases to allow two adjacent genes to overlap by"}
 op:option{"-d", action='store_true', dest='debug',
                 help="output debug information on stderr"}
 options,args = op:parse({threshold=0.6, minratio=0.8, maxratio=1.2,
-                         debug=false, rejectfile=nil,
+                         debug=false, rejectfile=nil, mapping=nil,
                          ignore_frame_agreement=false, longest_until=4})
 
 function usage()
@@ -59,6 +64,18 @@ if #args < 2 then
   usage()
 end
 
+if options.mapping then
+  local mapfile = io.open(options.mapping, "rb")
+  if not mapfile then
+    error("could not open reference target mapping file")
+  end
+  local mapcontent = mapfile:read("*all")
+  mapfile:close()
+  ref_target_mapping = json.decode(mapcontent)
+else
+  ref_target_mapping = nil
+end
+
 local rejected_pseudogenes = {}
 local rm = gt.region_mapping_new_seqfile_matchdescstart(args[2])
 
@@ -381,7 +398,7 @@ function stream:next_tree()
           else
             if self.last_seqid == fn:get_seqid()
                 and self.last_strand == fn:get_strand()
-                and self.curr_rng:overlap(new_rng) then
+                and conditional_overlap(ref_target_mapping, self.curr_rng, new_rng, self.last_seqid, options.overlap) then
               table.insert(self.curr_gene_set, fn)
               self.curr_rng = self.curr_rng:join(new_rng)
             else