P8 complete: scientific validation on GSE165845 vs NYGC 30x and GIAB HG001

360 GSA arrays (120 1000 Genomes individuals x 3 replicates): concordance 0.9934 vs
NYGC 30x (0.9958 on sites in both sets), 0.9985 vs GIAB HG001 v4.2.1 (non-ref F1
0.997), replicate concordance 0.9966; allele-swap sites 0.016 %; 358/360 replicate
pairs detected as duplicates. Plan §16.5 metrics in docs/validation/P8.md (K-024).

docs/known_unknowns.md

@@ -4,6 +4,7 @@ Plan §20 lists the open questions; this file records what the implementation ha
 
 | ID | Date | Topic | Finding | Status |
 |---|---|---|---|---|
+| K-024 | 2026-09-28 | GSE165845 (P8) | GSA-MD v1 chips have no public cluster file; the GSA v1 C1 EGT with the C2 build-38 BPM covers 99.996 % of bead addresses and gives median LogR deviation 0.246 (cluster mismatch, not noise). GSM5051309 (NA20362 rep 2) is a failed array (call rate 0.762, concordance 0.336 with its own replicates). 27 510 array records have no NYGC 30x record and are scored as hom-ref; 1444 of them are systematically called alt. | Recorded in `docs/validation/P8.md`; results reported with and without these. |
 | K-023 | 2026-09-28 | P6 optional outputs | Implemented and validated the same day: `--info-fields` (with `--egt`), `--extra-format`, `--merge-snv-indel`, `--auxiliary-loci`, PLINK 2 `.pgen`. Two decisions: OUT-035 rule (d) uses the MNV's last plus-strand base for minus-strand designs (spec amended); `--extra-format` writes NORMX/NORMY missing where the raw intensities are both 0, and THETA/R missing where both normalized intensities are 0 (148 values on 3 GSA samples; gtc2vcf writes 0). | resolved |
 | K-022 | 2026-09-28 | VCF oracles' limits (GSA v4 PGx, GRCh38) | gtc2vcf leaves 144 indel probes unresolved (`REF=I`/`D`) that SimurgArray resolves from `SourceSeq`; both leave 49 indels unresolved. GTCtoVCF (python-2.7 era) runs under Python 3 only with two local patches (pyvcf3 `Format` field; skip instead of crash on 3 CYP2D6 indels whose `SourceSeq` has the dash on the right, `[ALLELE/-]`, which SimurgArray handles), and needs the alt-contig loci filtered when the FASTA has no alts. Neither oracle applies ploidy (males' X/Y/MT hets stay diploid). | documented |
 | K-021 | 2026-09-28 | Control metrics on legacy Omni2.5 IDATs | (1) The Omni2.5 manifest lists two bead addresses per control (e.g. 27630314 and 127630314, two bead-pool versions); only one is on a given chip. Absent addresses were NaN and poisoned the bead mean → 1794/2141 samples falsely flagged on both staining metrics. Absent addresses are now skipped. (2) 1290 samples have Biotin (Bgnd) green = 0 exactly (background-subtracted), so staining green is signal/0; QC-008 now defines that as +Inf (pass) and only 0/0 as NaN (flag). | resolved (spec QC-008 amended) |