add example where all individuals are missing one parent

pyrat-api-single-parent-mother.json

@@ -0,0 +1,16 @@
+[
+    {
+        "animalid": 101,
+        "eartag_or_id": "ID-101",
+        "mutations": [
+            {
+                "animalid": 101,
+                "mutation_id": 5,
+                "mutationname": "Mut-A",
+                "mutationtype": "BAC transgenic",
+                "grade_id": 5,
+                "mutationgrade": "het"
+            }
+        ]
+    }
+]

pyrat-api-single-parent-offspring.json

@@ -0,0 +1,58 @@
+[
+    {
+        "animalid": 1,
+        "eartag_or_id": "ID-001",
+        "species_name": "Mouse",
+        "sacrifice_reason_name": "Not usable age",
+        "dateborn": "2026-02-03T00:00:00",
+        "strain_name": "Line-A",
+        "mutations": [
+            {
+                "animalid": 1,
+                "mutation_id": 5,
+                "mutationname": "Mut-A",
+                "mutationtype": "BAC transgenic",
+                "grade_id": 5,
+                "mutationgrade": "het"
+            }
+        ],
+        "parents": [
+            {
+                "animalid": 1,
+                "parent_id": 101,
+                "parent_eartag": "ID-101",
+                "parent_sex": "f",
+                "parent_labid": "B",
+                "parent_cagenumber": "B2"
+            }
+        ]
+    },
+    {
+        "animalid": 2,
+        "eartag_or_id": "ID-002",
+        "species_name": "Mouse",
+        "sacrifice_reason_name": "Not usable age",
+        "dateborn": "2026-02-04T00:00:00",
+        "strain_name": "Line-A",
+        "mutations": [
+            {
+                "animalid": 2,
+                "mutation_id": 5,
+                "mutationname": "Mut-A",
+                "mutationtype": "BAC transgenic",
+                "grade_id": 5,
+                "mutationgrade": "wt"
+            }
+        ],
+        "parents": [
+            {
+                "animalid": 2,
+                "parent_id": 101,
+                "parent_eartag": "ID-101",
+                "parent_sex": "f",
+                "parent_labid": "B",
+                "parent_cagenumber": "B2"
+            }
+        ]
+    }
+]

pyrat-api-single-parent.csv

@@ -0,0 +1,3 @@
+ID,Species,Sacrifice reason,DOB,Line / Strain (Name),Mutation 1,Grade 1,Mother,Father,Mother: Mutation 1,Mother: Grade 1,Father: Mutation 1,Father: Grade 1
+ID-001,Mouse,Not usable age,2026-02-03,Line-A,Mut-A,het,ID-101,,Mut-A,het,,
+ID-002,Mouse,Not usable age,2026-02-04,Line-A,Mut-A,wt,ID-101,,Mut-A,het,,