78cdae7249c8609dcbc743e996ea7e5eec33d75a
max
  Mon Aug 17 08:15:39 2026 -0700
lrSv: fix off-by-one anchor base in deletion coordinates across converters, refs #38099

VCF/pangenome deletions carry a non-deleted anchor (padding) base at POS.
Several lrSv converters set chromStart = pos-1, which includes that anchor, so
each deletion was 1 bp too wide on the left and svLen was 1 too big. Callsets
handled this inconsistently, so the same deletion appeared at offset coordinates
and failed to merge in lrSvAll.

For deletions only (INS/INV/CPX unchanged), advance chromStart past the anchor
so the interval covers exactly the deleted bases (svLen == |SVLEN|). Verified
against the hg38 reference: the old left base is present in both REF and ALT
(i.e. retained by the sample), so it should not be inside the deletion.

Fixed 11 converters: lrSv1kLin1218VcfToBed, lrSv1kgOntVcfToBed,
lrSvGustafsonVcfToBed, lrSvGa4kSvVcfToBed, lrSvDecodeVcfToBed,
lrSvAou1kCsvToBed, lrSvColorsDbSvVcfToBed, lrSvCardBbToBed, lrSvAprVcfToBed,
lrSvCpc1VcfToBed, lrSvVcfToBed (generic, used by han945).

Left unchanged, verified already anchor-correct: hgsvc3 and hgsvc2 (0-based
source), hprc2v21 (Ro converter prefix-trims), noyvert/tommoJp (POS is the
first deleted base), chirmade101 (1-based-closed source).

Rebuilt all affected bigBeds (hg38 + hs1 where present) and the lrSvAll merge:
3,111,026 -> 2,963,093 rows as ~148k duplicate deletions now merge.

diff --git src/hg/makeDb/scripts/lrSv/lrSvAprVcfToBed.py src/hg/makeDb/scripts/lrSv/lrSvAprVcfToBed.py
index 11742f0293c..34cdc5e9ac0 100755
--- src/hg/makeDb/scripts/lrSv/lrSvAprVcfToBed.py
+++ src/hg/makeDb/scripts/lrSv/lrSvAprVcfToBed.py
@@ -1,183 +1,188 @@
 #!/usr/bin/env python3
 """Convert Arabic Pangenome Reference (APR) pangenome VCF on T2T-CHM13v2
 to a bed9+7 table for the lrSv/aprSv track.
 
 Input VCF characteristics (unlike the CPC VCF this one is NOT decomposed):
   * contigs are named "chr1", "chr2", ... with CHM13v2 lengths
   * variant IDs are graph snarl IDs like "<951452<1012008"
   * REF/ALT are explicit sequences
   * each snarl appears on a single row, with multi-allelic ALT
     (comma-separated). INFO AC/AF are comma lists of the same length.
 
 This script:
   1. iterates the comma-separated alt alleles within each VCF row
   2. classifies each alt by length delta d = len(ALT)-len(REF):
          d >= +50   -> INS
          d <= -50   -> DEL
          |d| < 50 and max(len) >= 50 -> CPX
          otherwise  -> dropped
   3. emits one bed row per snarl (row) with alts merged:
          svType = agreed class or MIXED if alts differ
          svLen  = reference span (chromEnd - chromStart)
          insLen = max inserted-sequence length across passing INS alts (0 otherwise)
          AC     = sum of AC values for passing alts
          alleleNumber = AN (constant)
          alleleFreq   = AC / alleleNumber
      Rows with zero passing alts are skipped.
 
 Usage:
     lrSvAprVcfToBed.py input.vcf.gz output.bed chrom.sizes
 """
 
 import gzip
 import os
 import sys
 
 sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
 from lrSvCommon import svName, normalizeSvType, svColor
 
 SIZE_THRESHOLD = 50
 
 
 def parse_info(info_str):
     d = {}
     for token in info_str.split(";"):
         if not token:
             continue
         if "=" in token:
             k, v = token.split("=", 1)
             d[k] = v
         else:
             d[token] = True
     return d
 
 
 def classify(ref_len, alt_len):
     d = alt_len - ref_len
     if d >= SIZE_THRESHOLD:
         return "INS", d
     if d <= -SIZE_THRESHOLD:
         return "DEL", -d
     if max(ref_len, alt_len) >= SIZE_THRESHOLD:
         return "CPX", max(ref_len, alt_len)
     return None, 0
 
 
 def _int(val, default=0):
     try:
         return int(str(val))
     except (ValueError, TypeError):
         return default
 
 
 def main():
     if len(sys.argv) < 4:
         sys.exit("usage: lrSvAprVcfToBed.py input.vcf.gz output.bed chrom.sizes")
     in_file = sys.argv[1]
     out_file = sys.argv[2]
     sizes_file = sys.argv[3]
 
     chrom_sizes = {}
     with open(sizes_file) as f:
         for line in f:
             c, s = line.strip().split("\t")
             chrom_sizes[c] = int(s)
 
     opener = gzip.open if in_file.endswith(".gz") else open
 
     emitted = 0
     skipped_no_sv_alt = 0
     skipped_chrom = 0
     total_alts_seen = 0
 
     with opener(in_file, "rt") as fin, open(out_file, "w") as fout:
         for line in fin:
             if line.startswith("#"):
                 continue
             f = line.rstrip("\n").split("\t", 8)
             chrom, pos, vid, ref, alt, qual, filt, info = f[:8]
 
             if chrom not in chrom_sizes:
                 skipped_chrom += 1
                 continue
 
             alts = alt.split(",")
             total_alts_seen += len(alts)
             info_d = parse_info(info)
 
             ac_list = info_d.get("AC", "").split(",")
             af_list = info_d.get("AF", "").split(",")
             an = _int(info_d.get("AN", "0"))
             ns = _int(info_d.get("NS", "0"))
             ref_len = len(ref)
 
             types = set()
             max_mag = 0
             max_ins = 0
             ac_sum = 0
             num_pass = 0
             for i, alt_seq in enumerate(alts):
                 sv_type, mag = classify(ref_len, len(alt_seq))
                 if sv_type is None:
                     continue
                 types.add(sv_type)
                 if mag > max_mag:
                     max_mag = mag
                 if sv_type == "INS":
                     d = len(alt_seq) - ref_len
                     if d > max_ins:
                         max_ins = d
                 if i < len(ac_list):
                     ac_sum += _int(ac_list[i])
                 num_pass += 1
 
             if num_pass == 0:
                 skipped_no_sv_alt += 1
                 continue
 
             sv_type = next(iter(types)) if len(types) == 1 else "MIXED"
             sv_type = normalizeSvType(sv_type)
             rgb = svColor(sv_type)
 
             pos0 = int(pos) - 1
             start = pos0
             end = start + max(ref_len, 1)
+            # For DEL, POS is the non-deleted anchor base; drop it from the left
+            # (end already = pos-1+ref_len). The shared prefix is >=1 base so this
+            # never over-shifts. Only DEL moves; INS/MIXED keep the anchor.
+            if sv_type == "DEL":
+                start += 1
             af = (ac_sum / an) if an else 0.0
             score = min(1000, max(0, int(round(af * 1000))))
 
             svLen = end - start
             if sv_type == "INS":
                 insLen = max_ins
             else:
                 insLen = 0
 
             featLen = insLen if sv_type in ("INS", "MEI") else svLen
             name = svName(sv_type, featLen, ac_sum)
 
             row = [
                 chrom, str(start), str(end),
                 name,
                 str(score),
                 ".",
                 str(start), str(end),
                 rgb,
                 sv_type,
                 str(svLen),
                 str(insLen),
                 str(ac_sum),
                 str(num_pass),
                 str(an),
                 f"{af:.6f}",
                 str(ns),
             ]
             fout.write("\t".join(row) + "\n")
             emitted += 1
 
     print(f"total alt alleles seen: {total_alts_seen}", file=sys.stderr)
     print(f"emitted sites (>=1 SV alt): {emitted}", file=sys.stderr)
     print(f"skipped rows (no SV alt): {skipped_no_sv_alt}", file=sys.stderr)
     print(f"skipped rows (bad chrom): {skipped_chrom}", file=sys.stderr)
 
 
 if __name__ == "__main__":
     main()