Assessing the evidential value of DNA profiles matching without using the assumption of independent loci

DNA profiling allows determination of the alleles at multiple loci on an individual's genome. The frequencies of these alleles are then estimated from a sample drawn from the population. If the occurrences of alleles at different loci are independent, the frequencies may be multiplied together to give an estimate of the probability of DNA from a randomly-chosen member of the population matching the DNA in question. However, there is doubt as to whether the assumption of independence can be justified. This paper discusses a method of calculating the probability of a match that does not require the assumption of independence. A suitable set of criteria is also derived that offer an objective approach to the determination of a match from two DNA samples.