Demonstrating that penetration has occurred when no semen is found: the whys and wherefores of Y-STRs

Human chromosomes - Y-STR tests areas of the Y chromosome

Evidence to demonstrate that penile or digital penetration of the vagina has taken place can be difficult to find in some cases.  Traditional DNA profiling techniques can’t really help as the few male cells potentially deposited are overwhelmed by the large amount of female DNA present in the vaginal cells.  Y-STR typing is a form of DNA analysis that targets just the DNA present on the male Y chromosome allowing production of a male Y-STR profile even in the presence of seemingly overwhelming amounts of female DNA.READ MORE