5e4ca58df1b5bfe554fe5cc3309a39736ca256ee
max
  Tue Apr 21 08:08:52 2026 -0700
cpc1Sv: restrict to the 58 CPC samples, drop HPRC-specific SVs

Rewrite lrSvCpc1VcfToBed.py to identify the 58 CPC sample columns by
name prefix (HIFI032* or RY*), recompute AC/AN/NS from those GT
columns only, and skip any snarl that no CPC sample carries. The
HPRC portion is already represented elsewhere in lrSv, so this keeps
the track population-consistent with its label.

Rebuild results: 46,092 snarl sites on hs1 (down from 97,205 when
combined with HPRC), 36,030 lifted to hg38 (down from 81,261;
10,062 unmapped). Updates cpc1Sv.html, lrSv.ra labels, and the
makeDoc.

refs #36258

diff --git src/hg/makeDb/scripts/lrSv/lrSvCpc1VcfToBed.py src/hg/makeDb/scripts/lrSv/lrSvCpc1VcfToBed.py
index 5faecd7ce9c..13f01328ff0 100755
--- src/hg/makeDb/scripts/lrSv/lrSvCpc1VcfToBed.py
+++ src/hg/makeDb/scripts/lrSv/lrSvCpc1VcfToBed.py
@@ -1,204 +1,229 @@
 #!/usr/bin/env python3
 """Convert the CPC+HPRC Phase 1 pangenome VCF (on T2T-CHM13v2) to a
-bed9+7 table for the lrSv/cpc1Sv track.
+bed9+7 table for the lrSv/cpc1Sv track, RECOMPUTING AC/AN/NS using only
+the 58 CPC (Chinese Pangenome Consortium) sample columns and dropping
+snarls with no CPC carriers.
 
 The input VCF is produced by vcfwave/bcftools norm from a pangenome
 graph, so:
   * contigs are named "CHM13v2.chrN"
   * variant IDs are graph snarl traversals like ">2541>2547"
   * REF and ALT are always explicit sequences (no symbolic ALTs)
   * each snarl may appear as several rows, one per decomposed alt allele
-
-This script:
-  1. strips the "CHM13v2." contig prefix (hs1 chrom names)
-  2. classifies each alt allele by length delta d = len(ALT)-len(REF):
+  * the 105 sample columns are 47 HPRC (HG*, NA*) + 58 CPC (HIFI032*, RY*)
+
+Pipeline:
+  1. Parse the #CHROM header to identify the 58 CPC sample column indices
+     by prefix (HIFI032* or RY*).
+  2. Strip the "CHM13v2." contig prefix for hs1 chrom names.
+  3. For each VCF row, read the GT field for each CPC sample and compute
+     CPC-only AC (count of "1" alleles), AN (count of non-missing alleles),
+     and NS (CPC samples with at least one called allele).
+  4. Classify each alt allele by length delta d = len(ALT)-len(REF):
          d >= +50   -> INS
          d <= -50   -> DEL
          |d| < 50 and max(len) >= 50 -> CPX
          otherwise  -> dropped (below 50bp threshold)
-  3. groups all alt alleles that share the same graph snarl ID into one
-     output row, taking:
+  5. Drop rows where CPC AC == 0 (HPRC-specific alts).
+  6. Collapse all remaining alts sharing the same snarl ID into one output row:
          svType = that class if all alts agree, else MIXED
          svLen  = max |d| across alts
-         alleleCount = sum of per-alt AC
-         alleleNumber = AN (constant for the snarl)
+         alleleCount = sum of per-alt CPC AC
+         alleleNumber = CPC AN
          alleleFreq   = alleleCount / alleleNumber
-     The BED interval spans from POS-1 to POS-1 + len(REF).
+         numSamples   = CPC NS
 
 Usage:
     lrSvCpc1VcfToBed.py input.vcf.gz output.bed chrom.sizes
 """
 
 import gzip
 import sys
-from collections import defaultdict
 
 # Colors per SV type
 COLORS = {
     "INS": "0,0,200",       # blue
     "DEL": "200,0,0",       # red
     "CPX": "230,140,0",     # orange
     "MIXED": "120,120,120", # grey
 }
 
 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 is_cpc_sample(name):
+    """CPC samples are HIFI032* (Chinese, 47) and RY* (Chinese, 11)."""
+    return name.startswith("HIFI032") or name.startswith("RY")
 
 
 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 compute_cpc_counts(gt_cols):
+    """Return (ac, an, ns) across the given CPC GT strings for a single alt."""
+    ac = 0
+    an = 0
+    ns = 0
+    for gt in gt_cols:
+        # GT may be "0|0", "1|0", ".|1", ".|.", "0/1", etc.
+        has_called = False
+        for a in gt.replace("/", "|").split("|"):
+            if a == ".":
+                continue
+            an += 1
+            has_called = True
+            if a == "1":
+                ac += 1
+        if has_called:
+            ns += 1
+    return ac, an, ns
+
+
 def emit(site, fout):
-    """site is dict: chrom, pos0, ref_len, name, types (set), svlen,
-    ac_sum, an, ns."""
     classes = site["types"]
-    if len(classes) == 1:
-        sv_type = next(iter(classes))
-    else:
-        sv_type = "MIXED"
+    sv_type = next(iter(classes)) if len(classes) == 1 else "MIXED"
     rgb = COLORS[sv_type]
     chrom = site["chrom"]
     start = site["pos0"]
     end = start + max(site["ref_len"], 1)
     af = (site["ac_sum"] / site["an"]) if site["an"] else 0.0
     score = min(1000, max(0, int(round(af * 1000))))
     row = [
         chrom, str(start), str(end),
         site["name"],
         str(score),
         ".",
         str(start), str(end),
         rgb,
         sv_type,
         str(site["svlen"]),
         str(site["num_alts"]),
         str(site["ac_sum"]),
         str(site["an"]),
         f"{af:.6f}",
         str(site["ns"]),
     ]
     fout.write("\t".join(row) + "\n")
 
 
 def main():
     if len(sys.argv) < 4:
         sys.exit("usage: lrSvCpc1VcfToBed.py input.vcf.gz output.bed chrom.sizes")
     in_file = sys.argv[1]
     out_file = sys.argv[2]
     sizes_file = sys.argv[3]
 
-    # Load chrom sizes for validation / clipping
     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
 
-    # Accumulator: key = (chrom, pos0, snarl_id)
-    # We stream the file and flush a site whenever we encounter a new key,
-    # because the VCF is sorted and decomposed alts of the same snarl are
-    # adjacent.
+    cpc_col_idx = None  # set when we parse #CHROM header
+
     prev_key = None
     site = None
     kept_rows = 0
     dropped_small = 0
+    dropped_no_cpc_carrier = 0
     dropped_chrom = 0
     flushed_sites = 0
 
     with opener(in_file, "rt") as fin, open(out_file, "w") as fout:
         for line in fin:
-            if line.startswith("#"):
+            if line.startswith("##"):
                 continue
-            f = line.rstrip("\n").split("\t", 8)
-            chrom_raw, pos, vid, ref, alt, qual, filt, info = f[:8]
+            if line.startswith("#CHROM"):
+                # Sample columns start at index 9.
+                cols = line.rstrip("\n").split("\t")
+                sample_names = cols[9:]
+                cpc_col_idx = [
+                    9 + i for i, n in enumerate(sample_names) if is_cpc_sample(n)
+                ]
+                print(f"CPC samples found: {len(cpc_col_idx)}", file=sys.stderr)
+                if len(cpc_col_idx) == 0:
+                    sys.exit("ERROR: no CPC sample columns (HIFI032* or RY*) detected")
+                continue
+
+            if cpc_col_idx is None:
+                sys.exit("ERROR: data line before #CHROM header")
+
+            f = line.rstrip("\n").split("\t")
+            chrom_raw, pos, vid, ref, alt = f[0], f[1], f[2], f[3], f[4]
+
             if chrom_raw.startswith("CHM13v2."):
                 chrom = chrom_raw[len("CHM13v2."):]
             else:
                 chrom = chrom_raw
             if chrom not in chrom_sizes:
                 dropped_chrom += 1
                 continue
 
             ref_len = len(ref)
             alt_len = len(alt)
             sv_type, mag = classify(ref_len, alt_len)
             if sv_type is None:
                 dropped_small += 1
                 continue
 
-            info_d = parse_info(info)
-            def _int(val, default=0):
-                try:
-                    return int(str(val).split(",")[0])
-                except (ValueError, TypeError):
-                    return default
-            ac = _int(info_d.get("AC", 0))
-            an = _int(info_d.get("AN", 0))
-            ns = _int(info_d.get("NS", 0))
-            pos0 = int(pos) - 1
+            # Extract CPC GTs and compute AC/AN/NS
+            gt_cols = [f[i] for i in cpc_col_idx]
+            ac, an, ns = compute_cpc_counts(gt_cols)
+            if ac == 0:
+                dropped_no_cpc_carrier += 1
+                continue
 
+            pos0 = int(pos) - 1
             key = (chrom, pos0, vid)
             if key != prev_key:
                 if site is not None:
                     emit(site, fout)
                     flushed_sites += 1
                 site = {
                     "chrom": chrom,
                     "pos0": pos0,
                     "ref_len": ref_len,
                     "name": vid,
                     "types": set(),
                     "svlen": 0,
                     "num_alts": 0,
                     "ac_sum": 0,
                     "an": an,
                     "ns": ns,
                 }
                 prev_key = key
 
             site["types"].add(sv_type)
             if mag > site["svlen"]:
                 site["svlen"] = mag
             site["num_alts"] += 1
             site["ac_sum"] += ac
-            # AN, NS should be the same across alts of one site; keep max just in case
             if an > site["an"]:
                 site["an"] = an
             if ns > site["ns"]:
                 site["ns"] = ns
             kept_rows += 1
 
         if site is not None:
             emit(site, fout)
             flushed_sites += 1
 
-    print(f"kept alt rows:        {kept_rows}", file=sys.stderr)
+    print(f"kept alt rows (CPC carrier):   {kept_rows}", file=sys.stderr)
+    print(f"dropped no CPC carrier:        {dropped_no_cpc_carrier}", file=sys.stderr)
     print(f"dropped <{SIZE_THRESHOLD}bp alt rows: {dropped_small}", file=sys.stderr)
     print(f"dropped bad chrom:             {dropped_chrom}", file=sys.stderr)
     print(f"output sites:                  {flushed_sites}", file=sys.stderr)
 
 
 if __name__ == "__main__":
     main()