diff --git a/scripts/align_for_tree.py b/scripts/align_for_tree.py
index 475cc43..c21350d 100644
--- a/scripts/align_for_tree.py
+++ b/scripts/align_for_tree.py
@@ -1,4 +1,4 @@
-from Bio import SeqIO
+from Bio import SeqIO, AlignIO
 from Bio.SeqRecord import SeqRecord
 import shutil
 import argparse
@@ -8,27 +8,28 @@ def alignfortree(realign, align, reference, newoutput, build):
     if build != "genome":
         shutil.copy(realign, newoutput)
     else:
-        realigned = {s.id:s for s in SeqIO.parse(realign, "fasta")}
+        realigned_aln = AlignIO.read(realign, 'fasta')
+        insert_length = realigned_aln.get_alignment_length()
+        realigned = {s.id:s for s in realigned_aln}
         original = SeqIO.parse(align, "fasta")
         ref = SeqIO.read(reference, "genbank")
-
+        
         for feature in ref.features:
-                if feature.type =='gene':
-                    a =str((list(feature.qualifiers.items())[0])[-1])[2:-2]
-                    if a == "G":
-                        startofgene = int(list(feature.location)[0])
-                        endofgene =  int(list(feature.location)[-1])+1
-                        break
+            if feature.type =='gene' or feature.type=='CDS':
+                a =str((list(feature.qualifiers.items())[0])[-1])[2:-2]
+                if a == "G":
+                    startofgene = int(list(feature.location)[0])
+                    endofgene =  int(list(feature.location)[-1])+1
 
         for record_original in original:
             sequence_to_insert = realigned.get(record_original.id, None)
             if sequence_to_insert is None:
-                sequence_to_insert = '-' * (endofgene - startofgene)
+                sequence_to_insert = '-' * insert_length
             else:
                 sequence_to_insert = sequence_to_insert.seq
 
-            record_for_tree = record_original.seq.replace(record_original.seq[startofgene:endofgene], sequence_to_insert)
-            newrecord = SeqRecord(record_for_tree, id=record_original.id, description=record_original.description)
+            newseq = record_original.seq[:startofgene] + sequence_to_insert + record_original.seq[endofgene:]
+            newrecord = SeqRecord(newseq, id=record_original.id, description=record_original.description)
             records.append(newrecord)
 
         SeqIO.write(records, newoutput, "fasta")
diff --git a/workflow/snakemake_rules/core.smk b/workflow/snakemake_rules/core.smk
index e87b63e..8acf9a0 100644
--- a/workflow/snakemake_rules/core.smk
+++ b/workflow/snakemake_rules/core.smk
@@ -56,9 +56,9 @@ rule filter:
     output:
     	sequences = build_dir + "/{a_or_b}/{build_name}/filtered.fasta"
     params:
-    	group_by = config["filter"]["group_by"],
-    	min_coverage = lambda w: f'{w.build_name}_coverage>{config["filter"]["min_coverage"].get(w.build_name, 10000)}',
-    	subsample_max_sequences = lambda w: config["filter"]["subsample_max_sequences"].get(w.build_name, 1000),
+        group_by = config["filter"]["group_by"],
+        min_coverage = lambda w: f'{w.build_name}_coverage>{config["filter"]["min_coverage"].get(w.build_name, 10000)}',
+        subsample_max_sequences = lambda w: config["filter"]["subsample_max_sequences"].get(w.build_name, 1000),
         strain_id=config["strain_id_field"],
     shell:
         """
@@ -185,9 +185,9 @@ rule refine:
         tree = build_dir + "/{a_or_b}/{build_name}/tree.nwk",
         node_data = build_dir + "/{a_or_b}/{build_name}/branch_lengths.json"
     params:
-    	coalescent = config["refine"]["coalescent"],
-    	clock_filter_iqd = config["refine"]["clock_filter_iqd"],
-    	date_inference = config["refine"]["date_inference"],
+        coalescent = config["refine"]["coalescent"],
+        clock_filter_iqd = config["refine"]["clock_filter_iqd"],
+        date_inference = config["refine"]["date_inference"],
         strain_id=config["strain_id_field"],
     shell:
         """
@@ -257,7 +257,7 @@ rule traits:
     log:
         "logs/{a_or_b}/traits_{build_name}_rsv.txt"
     params:
-    	columns = config["traits"]["columns"],
+        columns = config["traits"]["columns"],
         strain_id=config["strain_id_field"],
     shell:
         """
diff --git a/workflow/snakemake_rules/export.smk b/workflow/snakemake_rules/export.smk
index 6d8e9ec..1766996 100644
--- a/workflow/snakemake_rules/export.smk
+++ b/workflow/snakemake_rules/export.smk
@@ -39,7 +39,7 @@ rule export:
         auspice_json =  build_dir + "/{a_or_b}/{build_name}/tree.json",
         root_sequence = build_dir + "/{a_or_b}/{build_name}/tree_root-sequence.json"
     params:
-    	title = lambda w: f"RSV-{w.a_or_b.upper()} phylogeny",
+        title = lambda w: f"RSV-{w.a_or_b.upper()} phylogeny",
         strain_id=config["strain_id_field"],
         metadata_colors = lambda w: '' if w.build_name=='genome' else f"--color-by-metadata clade"
     shell: