ABSTRACT
In order to fully utilize the Y chromosome for forensic purposes, it is necessary to understand precisely what makes it such a unique chromosome. e usual absence of Y chromosomes in females allows the use of the Y chromosome as a marker for human sex identication, which can add helpful information in forensic investigations. e strict male-specic inheritance of the NRY provides opportunities to specically analyze DNA components of a crime scene sample that were provided by males only, and dierentiate them from those provided by females, which can be highly important in mixed stain analysis in forensics such as in cases of sexual assault. At the same time, recombinationfree inheritance from fathers to sons, combined with low to moderate mutation rates of most NRY-DNA polymorphisms, means that male relatives usually share the same NRY polymorphisms. is feature has both advantages and disadvantages for forensic applications of Y chromosome DNA. Disadvantages come in the way that conclusions from Y-chromosome DNA analysis usually cannot be made on an individual level, as desired in forensic investigation. is is because in the event of a matching Y-DNA prole between samples from a suspect and a crime scene the hypotheses that either the suspect or alternatively, any of his paternal male relatives, has le the crime scene sample have the same estimated probability (but see below for potential solution). Advantages are that because of shared Y-DNA proles between male relatives, a close paternal male relative of a deceased alleged father can be used to replace the father in paternity testing of a male ospring using Y-DNA analysis in deciency cases, where autosomal DNA proling oen is not informative. e same principle can also be used in disaster victim identication (DVI) of males using close or distant paternal male relatives in cases where autosomal DNA proling fails.
