// idea is to keep track of the disparity between two pools as a measure of FFPE degradation,
// or overall oxidation affecting tissue sample.
//possible SNP changes:
//
//
// * A C G T
// A * 1 2 3
// C 4 * 5 6
// G 7 8 * 9
// T 10 11 12 *
//
public static SignatureSorterResultFiles StrainVcf(VQROptions options)
{
var variantList = new List <CalledAllele>()
{
};
var basicCountsData = new CountData();
var edgeVariantsCountData = new EdgeIssueCountData(options.ExtentofEdgeRegion);
string basicCountsPath = CleanUpOldFiles(options.VcfPath, options.OutputDirectory, ".counts");
string edgeCountsPath = CleanUpOldFiles(options.VcfPath, options.OutputDirectory, ".edgecounts");
string edgeVariantsPath = CleanUpOldFiles(options.VcfPath, options.OutputDirectory, ".edgevariants");
using (AlleleReader readerA = new AlleleReader(options.VcfPath))
{
while (readerA.GetNextVariants(out variantList))
{
foreach (var variant in variantList)
{
try
{
basicCountsData.Add(variant);
edgeVariantsCountData.Add(variant, edgeVariantsPath);
}
catch (Exception ex)
{
Logger.WriteToLog(string.Format("Fatal error processing vcf; Check {0}, position {1}. Exception: {2}",
variant.Chromosome, variant.ReferencePosition, ex));
throw;
}
}
}
//The edge issue filter trails N variants behind.
//The following code cleans out the buffer, processing anything left behind in the buffer.
for (int i = 0; i < options.ExtentofEdgeRegion; i++)
{
edgeVariantsCountData.Add(null, edgeVariantsPath);
}
if (options.LociCount > 0)
{
basicCountsData.ForceTotalPossibleMutations(options.LociCount);
edgeVariantsCountData.ForceTotalPossibleMutations(options.LociCount);
}
if (options.DoBasicChecks)
{
CountsFileWriter.WriteCountsFile(basicCountsPath, basicCountsData);
}
if (options.DoAmpliconPositionChecks)
{
CountsFileWriter.WriteCountsFile(edgeCountsPath, edgeVariantsCountData);
}
}
return(new SignatureSorterResultFiles(basicCountsPath, edgeCountsPath, edgeVariantsPath));
}
public static void WriteCountsFile(string outFile, CountData counts)
{
using (var writer = new StreamWriter(new FileStream(outFile, FileMode.Create)))
{
writer.WriteLine();
writer.WriteLine("CountsByCategory");
foreach (MutationCategory mutation in counts.CountsByCategory.Keys)
{
writer.WriteLine(mutation + "\t" + counts.CountsByCategory[mutation]);
}
writer.WriteLine();
writer.WriteLine("AllPossibleVariants\t" + counts.NumPossibleVariants);
writer.WriteLine("VariantsCountedTowardEstimate\t" + counts.TotalMutations);
writer.WriteLine("MismatchEstimate(%)\t{0:N4}", (counts.ObservedMutationRate * 100));
}
}
/// <summary>
/// This is a pretty naive reader. The mutation categories must be listed first, and the rates must be listed last, or the parsing fails.
/// There are some hard coded strings. Yes, maybe it should be in json.
/// </summary>
/// <param name="file"></param>
/// <returns></returns>
public static CountData ReadCountsFile(string file)
{
CountData variantCounts = new CountData();
bool inRateSection = false;
using (StreamReader sr = new StreamReader(new FileStream(file, FileMode.Open)))
{
string line;
while (true)
{
line = sr.ReadLine();
if (line == "")
{
continue;
}
if (line == null)
{
break;
}
if (inRateSection)
{
string[] splat = line.Split();
if (splat.Length < 2)
{
continue;
}
double result = -1;
if (!(double.TryParse(splat[1], out result)))
{
throw new IOException("Unable to parse counts from noise file " + file);
}
string firstWord = splat[0];
switch (firstWord)
{
case "AllPossibleVariants":
variantCounts.NumPossibleVariants += result;
break;
case "FalsePosVariantsFound":
case "ErrorRate(%)":
case "VariantsCountedTowardEstimate":
case "ErrorRateEstimate(%)":
case "MismatchEstimate(%)":
continue;
default:
//if its a mutation category - do something. Else do nothing
if (MutationCategoryUtil.IsValidCategory(firstWord))
{
MutationCategory category = MutationCategoryUtil.GetMutationCategory(firstWord);
//this category should always exist. this is just defensive
if (!variantCounts.CountsByCategory.ContainsKey(category))
{
variantCounts.CountsByCategory.Add(category, 0);
Logger.WriteWarningToLog("This counts file found a mutation category listed that this version of VQR is not aware of, and cannot process. Please check " + firstWord);
}
variantCounts.CountsByCategory[category] += result;
}
break;
}
}
if (line.Contains("CountsByCategory"))
{
inRateSection = true;
}
}
}
return(variantCounts);
}
private static QualityRecalibrationData GetRecalibrationTables(SignatureSorterResultFiles resultsFilePaths,
VQROptions options)
{
CountData BasicCounts = null;
CountData EdgeCounts = null;
QualityRecalibrationData recalibrationData = new QualityRecalibrationData();
if (options.DoBasicChecks)
{
if (!File.Exists(resultsFilePaths.BasicCountsFilePath))
{
Logger.WriteToLog("Cannot do basic recalibration. Cannot find {0} ", resultsFilePaths.BasicCountsFilePath);
}
else
{
Logger.WriteToLog("Found counts file: {0} ", resultsFilePaths.BasicCountsFilePath);
BasicCounts = CountsFileReader.ReadCountsFile(resultsFilePaths.BasicCountsFilePath);
recalibrationData.BasicLookupTable = GetPhredScaledCalibratedRates(options.BamFilterParams.MinimumBaseCallQuality, options.ZFactor, BasicCounts);
//if no work to do here...
if ((recalibrationData.BasicLookupTable == null) || (recalibrationData.BasicLookupTable.Count == 0))
{
Logger.WriteToLog("No general recalibration needed.");
}
else
{
Logger.WriteToLog("General mutation bias detected. This sample may have sample-specific prep issues such as FFPE or oxidation damage.");
}
}
}
if (options.DoAmpliconPositionChecks)
{
if (!File.Exists(resultsFilePaths.AmpliconEdgeCountsFilePath))
{
Logger.WriteToLog("Cannot do amplicon-position based recalibration. Cannot find {0} ", resultsFilePaths.AmpliconEdgeCountsFilePath);
}
else
{
Logger.WriteToLog("Found counts file: {0} ", resultsFilePaths.AmpliconEdgeCountsFilePath);
EdgeCounts = CountsFileReader.ReadCountsFile(resultsFilePaths.AmpliconEdgeCountsFilePath);
recalibrationData.AmpliconEdgeVariantsLookupTable = GetPhredScaledCalibratedRates(options.BamFilterParams.MinimumBaseCallQuality, options.ZFactor, EdgeCounts);
recalibrationData.AmpliconEdgeVariantsList = VariantListReader.ReadVariantListFile(resultsFilePaths.AmpliconEdgeSuspectListFilePath);
if ((recalibrationData.AmpliconEdgeVariantsLookupTable == null) || (recalibrationData.AmpliconEdgeVariantsLookupTable.Count == 0))
{
Logger.WriteToLog("No position-in-amplicon recalibration needed.");
}
}
}
//compare edge-issues with FFPE-like issues.
//Did the bulk of variants appear to come from the edge of amplicons..?
//Look at the diff in percents.
//If a variant is X more likely to be called when its by an edge - thats an estimate of the error.
if (options.DoBasicChecks && options.DoAmpliconPositionChecks)
{
recalibrationData.EdgeRiskLookupTable = GetPhredScaledCalibratedRatesForEdges(options.BamFilterParams.MinimumBaseCallQuality, options.AlignmentWarningThreshold, BasicCounts, EdgeCounts);
}
return(recalibrationData);
}
Dictionary <MutationCategory, int> GetPhredScaledCalibratedRates(int baselineQNoise, double zFactor, CountData counts)
{
double baseNoiseRate = MathOperations.QtoP(baselineQNoise);
var countsByCategory = counts.CountsByCategory;
var PhredScaledRatesByCategory = new Dictionary <MutationCategory, int>();
countsByCategory.Remove(MutationCategory.Deletion);
countsByCategory.Remove(MutationCategory.Insertion);
countsByCategory.Remove(MutationCategory.Other);
countsByCategory.Remove(MutationCategory.Reference);
double[] sortedFinalCounts = countsByCategory.Values.OrderBy(d => d).ToArray();
if (countsByCategory.Keys.Count != 12)
{
return(null);
}
//take the average value, throwing out the top two and bottom two outlyiers.
double numDataPoints = 8; //12 - 4;
double avg = 0;
for (int i = 2; i < 10; i++)
{
avg += (sortedFinalCounts[i] / numDataPoints);
}
//get the variance
double variance = 0;
for (int i = 2; i < 10; i++)
{
variance += ((avg - sortedFinalCounts[i]) * (avg - sortedFinalCounts[i]) / numDataPoints);
}
//threshold = avg + z * sigma
double threshold = avg + zFactor * Math.Sqrt(variance);
foreach (var cat in countsByCategory.Keys)
{
double mutationCount = countsByCategory[cat];
if (mutationCount > threshold)
{
//baseline noise level is 'b' .
//the observed transition-rate is how frequently we observe a vf >b.
//so our expected freq due to noise =
// (prob of observation f_i <= b) + (prob of observation f_i > b)
double observedNoiseRate = 0;
if (counts.NumPossibleVariants > 0)
{
observedNoiseRate = mutationCount / counts.NumPossibleVariants;
}
//deliberately taking floor instead of rounding.
PhredScaledRatesByCategory.Add(cat, (int)(MathOperations.PtoQ(observedNoiseRate + baseNoiseRate)));
}
}
return(PhredScaledRatesByCategory);
}
Dictionary <MutationCategory, int> GetPhredScaledCalibratedRatesForEdges(int baselineQNoise, double warningThreshold, CountData basicCountsData, CountData edgeIssueCountsData)
{
Dictionary <MutationCategory, int> AdjustedErrorRates = new Dictionary <MutationCategory, int>();
double GeneralEdgeRiskIncrease = edgeIssueCountsData.ObservedMutationRate / basicCountsData.ObservedMutationRate;
if (GeneralEdgeRiskIncrease > warningThreshold)
{
Logger.WriteToLog("Warning, high levels of mismatches detected at loci near edges, relative to all other loci, by a factor of " + GeneralEdgeRiskIncrease);
}
double MutationRateInEdge = edgeIssueCountsData.ObservedMutationRate;
double MuationsCalledNotInEdge = basicCountsData.TotalMutations - edgeIssueCountsData.TotalMutations;
double TotalLociNotInEdge = basicCountsData.NumPossibleVariants - edgeIssueCountsData.NumPossibleVariants;
double MutationRateNotInEdge = MuationsCalledNotInEdge / TotalLociNotInEdge;
//if the error rate at the edges was the same as the error rate in the middle,
// we would expect this many variants at the edges:
double NullHypothesisExpectedMismatches = MutationRateNotInEdge * edgeIssueCountsData.NumPossibleVariants;
double HowManyVariantsWeActuallySaw = edgeIssueCountsData.TotalMutations;
double HowManyAreProbablyWrong = edgeIssueCountsData.TotalMutations - NullHypothesisExpectedMismatches;
//error rate in edge region, Given You Called a Variant.
double EstimatedErrorRateInEdgeRegions = HowManyAreProbablyWrong / edgeIssueCountsData.TotalMutations;
foreach (var cat in edgeIssueCountsData.CountsByCategory.Keys)
{
double countsAtEdge = edgeIssueCountsData.CountsByCategory[cat];
double overallMutations = edgeIssueCountsData.TotalMutations;
double proportion = countsAtEdge / edgeIssueCountsData.TotalMutations;
//how much this particular variant category contributed to the error rate increase
double estimatedErrorRateByCategory = proportion * EstimatedErrorRateInEdgeRegions;
int riskAsQRate = (int)MathOperations.PtoQ(estimatedErrorRateByCategory);
AdjustedErrorRates.Add(cat, riskAsQRate);
}
return(AdjustedErrorRates);
}
