Match probabilities for multiple siblings

Abstract

A defendant whose dna profile matches that of a crime stain may argue that he has several, say n, brothers and that one of them may have been the origin of the crime stain. If the probability for any of the brothers considered separately to match the crime stain profile is p, we show that the probability that at least one of the n brothers match is strictly smaller than np. This latter quantity therefore is an easy to compute and conservative value to report. © 2011 Elsevier Ireland Ltd. All rights reserved.