diff --git a/metadata/db-xrefs.yaml b/metadata/db-xrefs.yaml
index 62c1cbe8..64c64385 100644
--- a/metadata/db-xrefs.yaml
+++ b/metadata/db-xrefs.yaml
@@ -3067,3 +3067,15 @@
       url_syntax: https://www.japonicusdb.org/gene/[example_id]
       example_id: JaponicusDB:SJAG_01143
       example_url: https://www.japonicusdb.org/gene/SJAG_01143
+- database: TreeGrafter
+  name: TreeGrafter-generated GO annotations
+  rdf_uri_prefix: http://identifiers.org/panther.family/
+  generic_urls:
+    - http://www.pantherdb.org/
+  entity_types:
+    - type_name: protein family
+      type_id: NCIT:C20130
+      id_syntax: PTN[0-9]{9}|PTHR[0-9]{5}|PTHR[0-9]{5}:SF[0-9]+
+      url_syntax: http://www.pantherdb.org/panther/lookupId.jsp?id=[example_id]
+      example_id: PANTHER:PTHR11455
+      example_url: http://www.pantherdb.org/panther/lookupId.jsp?id=PTHR10000