diff --git a/app/models/collection_sample_set.rb b/app/models/collection_sample_set.rb
new file mode 100644
index 00000000..8de9443d
--- /dev/null
+++ b/app/models/collection_sample_set.rb
@@ -0,0 +1,15 @@
+class CollectionSampleSet < RegisterSampleSet
+  attr :collection
+
+  def initialize(collection)
+    @collection = collection
+  end
+
+  def source_object
+    collection
+  end
+
+  def type_genomes
+    @type_genomes ||= collection.map(&:type_genomes).flatten.uniq
+  end
+end
diff --git a/app/models/genome/sample_set.rb b/app/models/genome/sample_set.rb
index 8259d7d5..5a4c3cf8 100644
--- a/app/models/genome/sample_set.rb
+++ b/app/models/genome/sample_set.rb
@@ -3,39 +3,3 @@ def sample_set
     @sample_set ||= GenomeSampleSet.new(self, source_hash)
   end
 end
-
-class GenomeSampleSet < SampleSet
-  attr :genome, :source_hash
-  def initialize(genome, source_hash)
-    @genome = genome
-    @source_hash = source_hash
-    @source_hash ||= {}
-  end
-
-  def source_object
-    genome
-  end
-
-  def samples
-    @samples ||=
-      source_hash[:samples]&.map { |k, v| GenomeSample.new(k, v) } || []
-  end
-
-  def retrieved_at
-    @source_hash[:retrieved_at]
-  end
-
-  def extra_biosamples
-    return [] if empty?
-
-    @source_extra_biosamples ||=
-      %i[derived_from sample_derived_from].map do |attribute|
-        next unless attr = unique_attributes[attribute]
-
-        attr.map do |i|
-          i.value.gsub(/.*: */, '').gsub(/[\.]/, '').split(/ *[,;-](?: and)? */)
-        end
-      end.flatten.compact.uniq - known_biosamples
-  end
-end
-
diff --git a/app/models/genome_sample_set.rb b/app/models/genome_sample_set.rb
new file mode 100644
index 00000000..13312a26
--- /dev/null
+++ b/app/models/genome_sample_set.rb
@@ -0,0 +1,34 @@
+class GenomeSampleSet < SampleSet
+  attr :genome, :source_hash
+  def initialize(genome, source_hash)
+    @genome = genome
+    @source_hash = source_hash
+    @source_hash ||= {}
+  end
+
+  def source_object
+    genome
+  end
+
+  def samples
+    @samples ||=
+      source_hash[:samples]&.map { |k, v| GenomeSample.new(k, v) } || []
+  end
+
+  def retrieved_at
+    @source_hash[:retrieved_at]
+  end
+
+  def extra_biosamples
+    return [] if empty?
+
+    @source_extra_biosamples ||=
+      %i[derived_from sample_derived_from].map do |attribute|
+        next unless attr = unique_attributes[attribute]
+
+        attr.map do |i|
+          i.value.gsub(/.*: */, '').gsub(/[\.]/, '').split(/ *[,;-](?: and)? */)
+        end
+      end.flatten.compact.uniq - known_biosamples
+  end
+end
diff --git a/app/models/register/sample_set.rb b/app/models/register/sample_set.rb
index e2cb4f3a..49fdcc08 100644
--- a/app/models/register/sample_set.rb
+++ b/app/models/register/sample_set.rb
@@ -3,44 +3,3 @@ def sample_set
     @sample_set ||= RegisterSampleSet.new(self)
   end
 end
-
-class RegisterSampleSet < SampleSet
-  attr :register, :genome_sample_sets
-
-  def initialize(register)
-    @register = register
-  end
-
-  def source_object
-    register
-  end
-
-  def type_genomes
-    @type_genomes ||= register.type_genomes.uniq
-  end
-
-  def genome_sample_sets
-    @genome_sample_sets ||= type_genomes.uniq.map(&:sample_set).compact
-  end
-
-  def samples
-    @samples ||= genome_sample_sets.map(&:samples).flatten
-  end
-end
-
-class CollectionSampleSet < RegisterSampleSet
-  attr :collection
-
-  def initialize(collection)
-    @collection = collection
-  end
-
-  def source_object
-    collection
-  end
-
-  def type_genomes
-    @type_genomes ||= collection.map(&:type_genomes).flatten.uniq
-  end
-end
-
diff --git a/app/models/register_sample_set.rb b/app/models/register_sample_set.rb
new file mode 100644
index 00000000..0cdfc779
--- /dev/null
+++ b/app/models/register_sample_set.rb
@@ -0,0 +1,23 @@
+class RegisterSampleSet < SampleSet
+  attr :register, :genome_sample_sets
+
+  def initialize(register)
+    @register = register
+  end
+
+  def source_object
+    register
+  end
+
+  def type_genomes
+    @type_genomes ||= register.type_genomes.uniq
+  end
+
+  def genome_sample_sets
+    @genome_sample_sets ||= type_genomes.uniq.map(&:sample_set).compact
+  end
+
+  def samples
+    @samples ||= genome_sample_sets.map(&:samples).flatten
+  end
+end