DNAtools (version 0.2-4)

Pnm_all: The exact distribution of the number of alleles in a m-person DNA mixture

Description

Computes the exact distribution of the number of alleles in a \(m\)-person DNA mixture typed with STR loci. For a m-person DNA mixture it is possible to observe \(1,\ldots,2\times m \times L\) alleles, where \(L\) is the total number of typed STR loci. The method allows incorporation of the subpopulation correction, the so-called \(\theta\)-correction, to adjust for shared ancestry. If needed, the locus-specific probabilities can be obtained using the locuswise argument.

Usage

Pnm_all(m, theta, probs, locuswise = FALSE)
Pnm_locus(m, theta, alleleProbs)

Arguments

m

The number of contributors

theta

The coancestery coefficient

probs

List of vectors with allele probabilities for each locus

locuswise

Logical. If TRUE the locus-wise probabilities will be returned. Otherwise, the probability over all loci is returned.

alleleProbs

Vectors with allele probabilities

Value

Returns a vector of probabilities, or a matrix of locuswise probability vectors.

Details

Computes the exact distribution of the number of alleles for a m-person DNA mixture.

References

T. Tvedebrink (2014). 'On the exact distribution of the number of alleles in DNA mixtures', International Journal of Legal Medicine; 128(3):427--37. <https://doi.org/10.1007/s00414-013-0951-3>

Examples

# NOT RUN {
  ## Simulate some allele frequencies:
  freqs <-  structure(replicate(10, { g = rgamma(n = 10, scale = 4, shape = 3); 
                                      g/sum(g)
                                    },
              simplify = FALSE), .Names = paste('locus', 1:10, sep = '.'))

  ## Compute \eqn{\Pr(N(m = 3) = n)}, \eqn{n = 1,\ldots,2 * L *m}, where \eqn{L = 10}
  ## here
  Pnm_all(m = 2, theta = 0, freqs)
  ## Same, but locuswise results
  Pnm_all(m = 2, theta = 0, freqs, locuswise = TRUE)
  
# }