Not quite, autosomal STR is what most think of when DNA analysis is mentioned in court cases, it's the test that can (sometimes) determine who the contributor is with a confidence that it was them or their identical twin. This test for the bra clasp test was based on partial data and as such could have matched one in four people in the courtroom as Conti or Vechiotti said at the appeal. Worthless, too many contributors, too small a sample, too much (almost certainly) masked.
It wasn't accepted at the Massei court either, he relied in the Y-haplotype which is not something that can identify to that degree, more like a blood test. Just how rare Raffaele's Y-haplotype is was unknown in 2011 (there's a database we checked but its incomplete) but there's enough of them that odds are that Y-haplotype suggests it was Raffaele's DNA. That doesn't mean that DNA
means anything though, this is
not the sort of DNA testing that is used in American and British courts.
Yes, kind of,though there are many more Y-haplotypes than blood types. However keep in mind even if it was one of a thousand that in Perugia there's a hundred thousand people, thus a hundred people could have also have contributed that Y-haplotype. When you consider all the people we
know were in that cottage just after the murder, all the Police, technicians, the boys who were at the discovery, the prosecution, the photographers etc each and every one of them increases the chance that one might have the same Y-haplotype. It's kind of like the fact that of a class of thirty people, odds are someone will share your birthday, it's not like it becomes 30 of 365 when calculating the probability.
My
guess is the odds would indicate that Y-haplotype suggests it was Raffaele's DNA, but that's off incomplete information. It's certainly neither definite or anywhere close to that, just a balance of probabilities shooting in the dark.
The obvious one is contamination, it laid in a pile of dust and trash for weeks on end with stuff blowing around, that's (very probably) why there's a total of four males in the clasp. For that trace amount of Raffaele's Y-haplotype to
mean anything it has to suggest he was actually the one who put it there, meaning he touched the bra clasp. That's why C&V found it unreliable, there's no reason to think Raffaele (and three other men) touched that tiny bra clasp, but under the edge of a dirty rug is an excellent place to find the sorts of things that might transmit trace and partial DNA.
Also Stefanoni's lab wasn't equipped to handle LCN/LT DNA, trace DNA transfers (and thus contaminates)
much easier It's the difference between something that might adhere from me to you when the wind is blowing and me having to hock a lugie in your face to get a decent transfer. HUGE difference. Contamination with LT/LCN is not a rare occurrence, it's something that special (beyond sterile) conditions must be employed to try to prevent. C&V go into that
here.
Lo and behold when the independent experts went to re-test the bra clasp and reproduce her results they found:
One rule of scientific work is reproducibility. When
real scientists do tests like this there's samples left that can be retested years--or decades--later, you've probably heard of re-tests exonerating people. Neither of these pieces of evidence, hailed as the best evidence against them, could ever be re-tested,and one decayed in storage under the auspices of the one who presented such dubious work in court, and there's definite reason (like she
testified to it in court!) to think she knew better.
p)
