61e501ff1e558ceb89d89ce46acb8fae1cb46cfc
angie
  Fri Aug 28 08:23:02 2026 -0700
Add representativeBacktrack: 1 for exclusion of 23599 for XFJ.3.1 because representative was removed and added back with another masked mut putting it one node deeper in the pre-masking tree which caused the exclusion to be applied only to that little branch.

diff --git src/hg/utils/otto/sarscov2phylo/branchSpecificMask.yml src/hg/utils/otto/sarscov2phylo/branchSpecificMask.yml
index 4c02deccd86..60977119e7d 100644
--- src/hg/utils/otto/sarscov2phylo/branchSpecificMask.yml
+++ src/hg/utils/otto/sarscov2phylo/branchSpecificMask.yml
@@ -126,30 +126,31 @@
     reversions: [ T21711C, C22032T, A22033C, G22034A, A22770G, A23012G, G26610A,
                   # Added 2024-03-01 because they're causing reversion branches with >= 100 samples.
                   # Unfortunately 6183 and 9142 will be incorrect in XDD, XDR, XDS.
                   T2790C, T4321C, G6183A, T9142C, C13339T, A22353C, G22556A, C22577G, T22674C,
                   T22686C, G22688A, T22813G, C22895G, A22896T, A22898G, T22916C, G22917T, A22942T,
                   A23005T, C23075T, G23599T, G23604C, T24378C, T26858C,
                   # Added 2024-04-15 by request from Cornelius Roemer, doesn't affect currently
                   # designated recombinants fortunately:
                   T21941G,
                 ]
     exclusions:
       # Cornelius requested exclusion of XFJ.3.1, some of whose descendants have a real G23599T reversion.
       # https://github.com/cov-lineages/pango-designation/commit/02d2cb6aa1155e4d0473fcb1ff345f472725be27
       - site: 23599
         representative: England/CLIMB-CM7YJM45/2025
+        representativeBacktrack: 1
       # Fede requested exclusion of XFJ.3 at 21617 and 21618, so XFJ.3.1 correctly shows S:I19V
       - site: 21617
         representative: USA/UT-UPHL-251003428161/2025
       - site: 21618
         representative: USA/UT-UPHL-251003428161/2025
       # Cornelius identified real G23599T reversions in descendant sublineages of XFG (TJ.1.1 and TK.1)
       - site: 23599
         representative: USA/CA-CDPH-500147572/2025
 
 JN.1:
     # Inherits from BA.2.86
     representative: Denmark/DCGC-661561/2023
     ranges: [ [ 23008, 23011 ],  # https://github.com/cov-lineages/pango-designation/issues/2510
             ]
     sites: [ 1871,          # https://github.com/sars-cov-2-variants/lineage-proposals/issues/1466