Dr. Larkin wasn't talking specifically about BK because they did not have any DNA evidence to examine at the time. She WAS talking about possibilities that could happen from the processing of DNA and why it was necessary for the defense to be able to examine the evidence. She also spoke about how relationships are determined in IGG which is a combination of science and also experiential judgement, she talked about problems that which can occur with developing an IGG. However, I don't think any of this would have been brought up if AT didn't have questions about the DNA in this case.
No, I'm saying if Blum was right, there were not enough diploid cells to get a complete STR profile. A partial profile could lead to a false identification. If it was a partial profile, and the identification was false, then the IGG would be wrong, too.
IMO, IF the DNA was partial due to being degraded by sitting on brass, and the ID was made on the partial DNA, THEN, both the STR profile and the IGG developed from the STR profile could be completely wrong. It would all come down to GIGO (Garbage In, Garbage Out.)
Howard Blum wrote that the sample was "20 skin cells (maybe less.)" in Eyes of a Killer, Chapter 4. All the literature I can find online about how many skin cells are needed to get an STR indicates that normally 80 skin cells are needed. The literature also indicates that some of the cells are destroyed in processing. So I have to really wonder how good is the STR in this case? Was it complete or partial?
Just to put into perspective how tiny the sample found on the snap of the sheath was: "A single square inch of skin has about 19 million cells."
Skin Fun Facts: Did you know…? Your skin is your largest organ and plays a vital role in detecting hot and cold, regulating your body temperature and
pdskin.com
"Currently, the optimum DNA input to the PCR for STR profiling is around 500 pg [[1], [2], [3]], which equates to approximately
80 diploid cells (∼6 pg/cell [4]). If the potential of DNA loss through workflow processing is not considered, any item from which 80 cells are collected should generate a full DNA profile."
If Blum is right they collected only 20 diploid cells or less.
"Many laboratories use commercially available STR amplification kits. Depending on the kit and reaction volume, the optimal concentration of input DNA will be in the range of 0.5ng – 2ng.
Adding too much or too little DNA to the amplification reaction can result in problems in the analysis."
Current forensic DNA analysis uses polymerase chain reaction (PCR) based short tandem repeat (STR) testing
nij.ojp.gov
A further problem with such a minuscule sample is that the entire sample would be used up in the testing process leaving the defense without any option to have another lab run the same testing process on part of the sample to see if the results are identical or not. In this case, we have a prosecutor who initially told the court that they were going to have to "trust them" on the DNA identification. From that point forward he has proceeded to drag his feet about giving the defense any information about the DNA testing process at all. IMO, it's not a good look nor should it be tolerated. A fundamental of the scientific process is the reproducibility of results - that you have to be able to replicate the results to prove if the process worked correctly or not.
Here, the sample is too small to give half of it to the defense, so the next option would be to give complete documentation of the findings and then the defense can run BK's DNA to see if it matches LE's findings.
What is going on in this case is one of the reasons why I don't like non-scientists being in control of scientific evidence. In this case we have one lawyer trying to hide a scientific process from another lawyer and her DNA experts. It is really ridiculous. There should be no reason for that whatsoever. Either the scientific process worked correctly or the results were questionable or it did not work. Regardless of which outcome, it must be completely exposed and examined. Further, the Judge, also a non-scientist, got involved in deciding what parts of a scientific process the defense may view. How would JJ know what is Germaine about the testing? This is certainly not his area of expertise.
IMO, we need to do better. Our court system owes that to all of us.