likestim {forensim} | R Documentation |
The likestim
function gives multiloci estimation of the number of contributors to a forensic DNA mixture
using likelihood maximization.
likestim(mix, freq, refpop = NULL, theta = NULL, loc=NULL)
mix |
a simumix object |
freq |
a tabfreq object containing the allele frequencies to use for the calculation |
refpop |
the reference population from which to extract the allele frequencies used in the likelihood
calculation. If tabfreq contains more than one population, refpop must be
specified, otherwise, refpop is set to default (NULL). |
theta |
a float from [0,1[ giving Wright's Fst coefficient. theta accounts for population subdivision while
computing the likelihood of the data. |
loc |
loci to be considered in the estimation. Default (set to NULL) corresponds to all loci. |
The number of contributors which maximizes the likelihood of the data observed in the mixture is searched in the discrete interval [1,6]. In most cases this interval is a plausible range for the number of contributors.
A matrix of dimension 1 x 2, the first column, max
, gives the maximum likelihood estimation of the number of contributors,
the second column
gives the corresponding likelihood value maxvalue
.
Hinda Haned <haned@biomserv.univ-lyon1.fr>
Haned H, Pontier D, Lobry JR, Pene L, Dufour AB.
Estimating the number of contributors to forensic DNA mixtures: Does maximum likelihood
perform better than maximum allele count? Submitted, 2009.
Egeland T, Dalen I, Mostad PF.
Estimating the number of contributors to a DNA profile. Int J Legal Med 2003, 117: 271-275
Curran JM, Triggs CM, Buckleton J, Weir BS. Interpreting DNA Mixtures in Structured Populations. J Forensic Sci 1999, 44(5): 987-995
likestim.loc
for maximum of likelihood estimations per locus
data(strusa) #simulation of 1000 genotypes from the Hispanic allele frequencies gen<-simugeno(strusa,n=c(0,0,100)) #4-person mixture mix4 <- simumix(gen,ncontri=c(0,0,4)) likestim(mix4,strusa,refpop="Hisp")