Add VCF detectedOriginalBuild meta-information

src/snps/io/writer.py

@@ -171,6 +171,9 @@ def _write_vcf(self):
             f'##detectedCompany="{self._snps.source}"',
         ]
 
+        if self._snps.build_original:
+            comment.append(f"##detectedOriginalBuild={self._snps.build_original}")
+
         df = self._snps.snps
 
         p = self._snps._parallelizer

src/snps/snps.py

@@ -76,6 +76,7 @@ def __init__(
         self._phased = False
         self._build = 0
         self._build_detected = False
+        self._build_original = 0
         self._output_dir = output_dir
         self._resources = Resources(resources_dir=resources_dir)
         self._parallelizer = Parallelizer(parallelize=parallelize, processes=processes)
@@ -103,6 +104,9 @@ def __init__(
             self._build = d["build"]
             self._build_detected = True if d["build"] else False
 
+            if self._build_detected:
+                self._build_original = self._build
+
             if not self._snps.empty:
                 self.sort()
 
@@ -381,6 +385,16 @@ def build_detected(self):
         """
         return self._build_detected
 
+    @property
+    def build_original(self):
+        """Original build of SNPs, before any remapping.
+
+        Returns
+        -------
+        int
+        """
+        return self._build_original
+
     @property
     def assembly(self):
         """Assembly of SNPs.