You were asked some questions on cross-examination about the reference -- the victim's reference strips, the DQ Alpha strips, and the polymarker strips?
Did you have an opportunity to review those strips as part of your examination of materials in this case?
The -- The items that were pointed out to you in cross-examination that Mr. Baker asked you about, whether those were the same alleles as Mr. Simpson had in his blood, in your view, did those alleles show any evidence at all of contamination of Mr. Simpson's blood with the reference vial?
Well, the scientific explanation is that one has to look at the sequence, which things were performed, and if, in fact, Mr. Simpson's blood from -- from the vial was to have contaminated those, then there are many steps, controls, that would have been processed simultaneously that would also exhibit contamination. And the fact that not -- not just one, but all of those, uniformly show absolutely no evidence of contamination, allows one to make very, very subjective judgments and be very objective about what they're seeing. And there's no evidence at all, because all those controls are negative, that any of that could be due to contamination.
Incidentally, Doctor, where were the Fitzco cards for the reference -- for the victim's reference strips, where were those prepared?
For the victims, it was in a completely separate part of the lab from where the processing of the stains was done. Part of the lab was called the evidence processing room; that's where the processing of all the samples, with the exception of the two victims' samples, were processed. They were processed in a separate lab called the serology lab, which is physically within the same building, but completely separated. There's absolutely -- I mean it's incomprehensible that there could be any contamination between those two reference vials of the victims and any of the other evidence.
You were also asked some questions about Item 52, the Department of Justice's DQ Alpha strip for that item. Again, did you see any evidence of contamination in that item?
I thought I could get it but it's --
MR. P. BAKER: Putting up on the board, Civil 1281. (Exhibit 1281 displayed.)
Yes. Relating to that and what is depicted in this particular figure, you could see at the top that there is a -- it says Item 52, and at the bottom it also says 52. What ended up happening at the Department of Justice, if we look at the column to -- to the right of the strips where the actual results are indicated, it says at the top, 1.2 -- I'm sorry, 1.1, 1.3. And then below that 1.3 with a trace. And then at the very bottom it says 1.1, 1.2, 1.3, very faint trace. Now, what, in fact, happened was when 52 was originally done, it was -- the top strip, it was -- it's one at the top of that figure. And what the analysts realized in looking at that was that there was -- in fact, that the 1.3 that is depicted there --
MR. P. BAKER: Objection, speculation, no foundation.
What they realized is that the 1.3 that was there could be due to -- reasons having to do with cross-hybridization. What they then did was to redo the hybridization for that, which is at the bottom, and that is a separate strip. It was repeated. I mean they did exactly what one would do in a situation where there was a question about the validity of this particular piece of evidence. They repeated it and they got the result at the bottom. What one can see at the bottom is that 1.3 essentially goes away when they repeated it. What that indicates -- that's a very, very strong indication that what we're dealing with here is cross-hybridization. Furthermore, it's a 1.1, 1.2 genotype; the prominent type. The significance of it being a 1.3 is paramount as giving this cross reaction. And the reason is that the -- the difference between the 1.2 and the 1.3 is a single base pair in that sequence. So the discrimination -- this is testing the ultimate ability of this test to discriminate between a 1.2 and a 1.3, and because there's a lot of DNA, it has led to this cross-hybridization. It's completely logical in terms of one being able to look at this and be very objective about looking at all the data, especially the fact that it was repeated, in being able to make that judgment.
So their results matched the 1.1, 1.2, that Department of Justice called in regard to this item?
Does that give you further comfort that this is simply cross-hybridization that's being seen here?
Now, you were also asked some questions about Colin Yamauchi's handling of the reference vial. Did you see any problems at all in the way Colin Yamauchi handled Mr. Simpson's reference vial in doing the sampling in this case?
MR. P. BAKER: Asked and answered.
(BY MR. LAMBERT) Mr. Baker asked you some questions about the approximately 3,000 nanograms of DNA that were on the socks.
MR. P. BAKER: 1300.
I'm sorry, 1300 nanograms of DNA on the socks. Is that an amount of DNA that's consistent with the blood being splattered on the socks at the time of the crime?
Now, you were also asked some questions -- Mr. Baker asked you some questions about transferring of DNA from one hand to another. Do you remember that you put it on one hand?
Is it important for laboratories to establish controls to ensure such transfers don't occur?
Do you see any problems whatsoever in their test results in this case as a result of any such transfers?
I do not. And even to just go a step farther -- I mean it's important to point out that the standards that were -- which were used in all three of these labs, and their handling of these particular items, is equal to, if not exceeding, the standards that are used in medical diagnostic labs in making important decisions regarding people's health, regarding DN
It's no different. And the standards were equally -- equal to, if not exceeding, that in the medical world.
Mr. Baker, talking about evidence -- Item 31, asked you some questions about subjectivity and PCR testing. And you said that occasionally there is some subjectivity involved in making judgments about those tests. How is that subjective judgment exercised by the people doing these DQ Alpha strips?
Well, it's based on experience and it's based on being objective in terms of looking at all the data. So it would be -- one needs to look at everything that took place in a series of experiments where one is -- where this is a part of that. And one needs to look at -- be very objective, look at all this data in terms of drawing conclusions, just as I did with No. 52, and what I call cross-hybridization. And the subjectivity is based on that experience and being objective and looking at all the data that one has to rely on. And again, I need to stress to you that oftentimes we have to do this and we have to look at this data and make subjective calls. And in the medical world, and I'm not trying to overdramatize it, we make life and death decisions based on this. At times you have to do it, and you have to look at all the cards on the table, and you have to make your best judgment based on all the facts. And that's what I believe was done here, and I believe that they did it accurately.
And in your view, did Gary Sims and Robin Cotton have the kind of experience and background that enables them to make those subjective judgments?
MR. P. BAKER: Irrelevant, argumentative.
(BY MR. LAMBERT) In regard to most of the PCR test results in this case, was the subjective judgment call even necessary, Dr. Popovich?
Finally, you were asked some questions about the relatively small number of nanograms in the Bundy blood drops. Do you remember those questions?
Is it uncommon in your experience in criminal cases for there to be a relatively low number of nanograms in evidence items?
As long as there is an amount that exceeds the threshold of the sensitivity of that task, it can be done and the results can be accurate.
The fact that not -- not just one, but all of those, uniformly show absolutely no evidence of contamination, allows one to make very, very subjective judgments and be very objective about what they're seeing.
It's incomprehensible that there could be any contamination between those two reference vials of the victims and any of the other evidence.
What one can see at the bottom is that 1.3 essentially goes away when they repeated it. What that indicates -- that's a very, very strong indication that what we're dealing with here is cross-hybridization.
The standards that were -- which were used in all three of these labs... is equal to, if not exceeding, the standards that are used in medical diagnostic labs in making important decisions regarding people's health.