dbExpect | R Documentation |

Computes the expected number of cell counts when comparing DNA profiles in a DNA database. For every pair of DNA profiles in a database the number of matching and partial matching loci is recorded. A match is declared if the two DNA profiles coincide for both alleles in a locus and a partial-match is recorded if only one allele is shared between the profiles. With a total of L loci the number of matching loci is 0,...,L and partial number of matches is 0,...,L-m, where m is the number of matching loci.

dbExpect( probs, theta = 0, k = c(0, 0, 1), n = 1, r = 0, R = 0, round = FALSE, na = TRUE, vector = FALSE, collapse = FALSE, wildcard = FALSE, no.wildcard = NULL, rare.allele = FALSE, no.rare.allele = NULL )

`probs` |
List of vectors with allele probabilities for each locus |

`theta` |
The coancestery coefficient |

`k` |
The vector of identical-by-descent probabilities, k=(k2,k1,k0), where for full-siblings k=c(1,2,1)/4. The default is k=c(0,0,1) refering to unrelated individuals. |

`n` |
Number of DNA profiles in the database |

`r` |
The probability assigned to the rare alleles (see rare allele
matching). If a vector must be of same length as |

`R` |
The probability assigned to alleles shorter or longer than allelic
ladder (see rare allele matching). If a vector must be of length 1 or 2, and
if a list it must be same length as |

`round` |
Whether or not the results should be rounded or not |

`na` |
Whether or not the off-elements should be returned as 0 or NA |

`vector` |
Whether or not the result should be returned as a matrix or vector. Note if 'collapse' is TRUE vector is ignored. |

`collapse` |
Logical (default FALSE). If TRUE the (m,p)-matrix will be collapased into a (2*m+p)-vector containing the total number of matching alleles. |

`wildcard` |
Should wildcards be used? |

`no.wildcard` |
Should 'w' wildcards be used? |

`rare.allele` |
Should rare allele matching be used? |

`no.rare.allele` |
Should 'r' rare allele loci be used? |

Computes the expected cell counts using a recursion formula. See Tvedebrink et al (2011) for details.

Returns a matrix (or vector, see above) of expected cell counts.

James Curran and Torben Tvedebrink

T Tvedebrink, PS Eriksen, J Curran, HS Mogensen, N Morling. 'Analysis of matches and partial-matches in Danish DNA reference profile database'. Forensic Science International: Genetics, 2011.

## Not run: ## Simulate some allele frequencies: freqs <- replicate(10, { g = rgamma(n=10,scale=4,shape=3); g/sum(g)}, simplify=FALSE) ## Compute the expected number for a DB with 10000 profiles: dbExpect(freqs,theta=0,n=10000) ## End(Not run)

Embedding an R snippet on your website

Add the following code to your website.

For more information on customizing the embed code, read Embedding Snippets.