All right. Thank you, ladies and gentlemen. Please be seated. Dr. Gerdes. The record should reflect all the jurors have rejoined us. Dr. John Gerdes is on the witness stand again undergoing redirect examination by Mr. Scheck.
Good afternoon (Sic), ladies and gentlemen of the jury.
THE JURY: Good afternoon.
REDIRECT EXAMINATION BY MR. SCHECK
Dr. Gerdes, Mr. Clarke asked you quite a few questions about retyping by other laboratories?
Now, in terms of an initial cross-contamination of samples at the LAPD, does it matter how many other laboratories typed the samples if they were cross-contaminated initially at LAPD?
No. Once you've accidentally or some other way transferred that DNA from one sample to another, it doesn't matter how many gene systems, how many different labs, it is always going to transfer, it is always going to type as the DNA that was transferred.
KEY QUOTENow, Mr. Clarke showed you what has been marked 564-F which is a series of slides, if I could put this up on the elmo, please, with respect to typing performed at the LAPD laboratory with respect to three of the five Bundy blood drop samples. Will you put that up there, please. In terms of--
In terms of what was handled by Collin Yamauchi between nine o'clock and 11:00 on the morning of June 14th, were samples 47, 48, 49, 50, 52 and the Rockingham glove all sampled at that time with Mr. Simpson's reference sample?
All right. And in terms of the drying of samples, and packaging of samples, were items 47, 48, 49, 50 and 52, along with Rockingham items, including item no. 12, the drops taken from the foyer of Mr. Simpson's home, were they all taken out of plastic bags, wet swatches and put into test tubes by Mr. Fung and Miss Mazzola without changing gloves and without changing papers on June 13th as is indicated under the section "Drying" on 6/13?
Well, based on your review of the testimony did Miss Mazzola and Mr. Fung take out of plastic bags swatches that they described were wet, put them into test tubes for drying on the evening of June 13th which included 47, 48, 49, 50 and 52, and the different samples collected at Rockingham?
All right. And that would comport with the section of the chart marked "Drying," correct?
And on June 14th in the morning did Mr. Fung and Miss Mazzola scrape out of test tubes using a pipette without changing gloves and without changing paper, put into bindles the swatches that they had previously dried on June 13th?
Now, is it--what is your opinion about the way that Mr. Fung and Miss Mazzola handled those samples on June 13th and on June 14th in terms of the danger of cross-contamination?
I think there is significant risk of cross-contamination because they didn't change gloves because they create aerosols when they try and scrape these little swatches out of the tube, and because they handled the reference sample at the same time as all of these other evidence items and because certain items--
And because certain items--a number of items, in fact, were mixed between crime scenes in terms of being handled at the same time.
Incidentally, item no. 12, the drops from the floor in the foyer from Mr. Simpson's residence, was that among the last samples collected on June 13th?
Do you know if those were among the last samples collected by Mr. Fung and Miss Mazzola on June 13th?
Are you familiar with the testimony and the records concerning the collection of the items at Rockingham?
And in terms of DNA concentration, was the concentration of item no. 12, in terms of human DNA, higher significantly than the Bundy blood drops?
All right. And when that sample is handled in conjunction with the Bundy blood drops, in the fashion that you have just reviewed on June 13th and on June 14th, does that create a danger of cross-contamination with that sample?
Yes, because you are handling a sample that has a large amount of DNA with samples that are degraded and small amounts of DNA.
Now, also--well, could you--could we circle on this--the evidence processing room on this flow chart as indicated 6/13 and 6/14. Could we draw a circle around that, Mr. Harris, and may I suggest pink. No, no, no, that is the evidence--
Dr. Gerdes, is it your testimony that it is in these procedures on June 13th and June 14th that unacceptable risks of cross-contamination occurred?
And if those--cross-contamination to those samples, Bundy blood drops and the Rockingham glove, occurred at that time, would results be replicated by Cellmark, DOJ, your own laboratory, if you typed these kind of samples, Dr. Blake, Dr. Henry Lee or anyone else you found, assuming that they performed the tests correctly?
With the Court's permission could we turn the lights up and I will go over to a chart.
And your Honor, at the same time I would like to put up on the elmo what has previously been marked as Defendant's 1165. These are the charts of the amounts of nanograms of DNA.
--was that one of the Bundy blood drops that was handled by Dennis Fung and Andrea Mazzola on June 13th?
Was it one of the items that Mr. Yamauchi handled at the same period that he was handling Mr. Simpson's reference sample?
This is when Mr. Yamauchi took out the stopper and the blood went through the chem wipe onto his glove?
Now, 52, in terms of which of the Bundy blood drops swatches were opened up from the bindles, when Mr. Yamauchi began handling them on the morning of June 14th, which of the items did he handle first?
Are you familiar with the estimate of the amount of human DNA in each of the Bundy blood drops, 47 through 52, as testified to by Gary Sims based on his calculation has from slot-blots, yield gels and the size of the swatches and their weight?
All right. Do you regard those as accurate estimates as to the total number of nanograms of human DNA in those items?
All right. On--and in terms of the yield gels, is it a fair statement that 47, 48, 49, 50 and 52 were samples that were severely degraded in terms of bacterial DNA.
How many nanograms of human DNA did Robin Cotton testify went into that particular result?
Were any other of the samples from which RFLP results obtained, were those handled in the presence of the reference sample and in the period where the reference sample was handled?
Is it your testimony, sir, that there were unacceptable risks of cross-contamination that are associated with the results on 47, 48, 49, 50 and 52?
Now, there are frequency estimates on the right side of this chart for all those items?
Yes. I mean--these are an estimate of at what percentage of the population or what incidents in the population you might find all of these genetic markers. Error rate has to do with an evaluation of the laboratory itself and the question of how good are they in terms of how often they might make a mistake. And so on the one hand you are talking about how many--if you do a hundred samples, how often would you make an error?
On the other hand, you are talking about assuming there were no errors, how often would you find this in the population?
Do you agree with the recommendation of the national research council that laboratory error rate ought to be measured by the use of external blind proficiency tests on samples that replicate case work?
In terms of their open proficiency tests, in your judgment do those proficiency tests replicate case work?
No, they don't include mixtures or degraded DNA samples, DNA's of low concentrations.
In terms of the study that you performed looking at all the strips and runs at the LAPD laboratory, do you have a judgment as to how that--how personnel at that laboratory handle samples?
From your study, is there an objective basis for making an assessment as to the risk of error until handling samples at the LAPD?
In your study of contamination at the Los Angeles Police Department, in terms of their runs and strips, did you make an assessment of extraction controls versus amplification controls?
The significance is that the contamination was found predominantly in the reagent extraction controls.
And what does that indicate about this phase of the DNA process where errors were correct?
It indicates that in handling samples in the early stages, the extraction stages in both of those areas, that is where the contamination is being introduced in terms of what we can objectively look at, which is their record on doing known samples over the course of that time period.
And does that include the evidence processing room as one of those stages that the extraction control would cover?
Now, turning to the results from 117, the rear gate, are you aware, from your review of the testimony, as to the amount of DNA on that sample?
In your judgment is that significantly different than the amount of DNA on the other Bundy blood drops?
The Bundy blood--and in terms of bacterial degradation, do you agree with the assessment of Gary Sims that 117 did not show evidence on yield gels of bacterial degradation?
Are you aware of Mr. Sims testimony and assessment as to the level of bacterial degradation on item 117?
Dr. Gerdes, does it make any sense to you, based on your knowledge of DNA quantitation, that samples collected on June 13th from the same area, that is 47, 48, 49, 50 and 52, would be so degraded in terms of bacterial contamination--bacteria, 117 would show no evidence of that?
All right. Does this data, in terms of the dates of collection and the conditions where those samples were collected, make sense to you scientifically?
What is your assessment of the--can you explain the difference in DNA amounts and degradation on 117 versus 47 through 52?
Are you aware of the testimony that the same methods of collection were employed by Dennis Fung in terms of putting the swatches from 117 into a plastic bag, taking them to the laboratory and drying them in test tubes and sampling the next day as was followed with 47?
All right. Given that the same procedures were followed and given that all these items were in the locations where they were recovered, does it make any sense to you scientifically that there should be no evidence of degradation in 117 and so much evidence of degradation in 47 through 52?
Have you looked at photographs of the scene where these different items were collected?
In terms of their locations, in terms of the methods of--same methods of collection and in terms of the results with respect to bacterial degradation and yield of human DNA, did these results--what is your assessment of these results?
Is that--have you relied on your microbiology background in terms of your postdoctorate work and your work as a DNA lab director?
Do those principles, basic scientific principles of microbiology and molecular genetics that you have been trained in, do those have application to an assessment of bloodstains, bacteria and substrates?
Have you read the literature from forensic laboratories that you've called demonstration papers that deal with degradation of samples taken from crime scenes?
Based on all of that, what is your assessment in terms of the data that the Bundy blood drops were severely degraded with bacteria and the rear gate sample 117 was not and the rear gate sample had 150 nanograms of DNA which was five times higher than any Bundy blood drop sample?
It doesn't seem to make sense to me that you should see about the same level of degradation and in fact on 117, which is an older sample, should have more degradation.
KEY QUOTEDr. Gerdes, I show you what's been marked as Prosecution's 260 entitled "Results of DNA analysis on the Bronco automobile." Were the results of the steering wheel, no. 29, from the laboratories, a 1.2, 1.1, 4?
And taken at face value would that indicate a mixture of some--could indicate a mixture of somebody with a 1.1, 1.2 and somebody that is a 4?
Now, with respect to item no. 31 and item no. 30, were those the only results from the Bronco console that were removed on June 14th?
In terms of the sample removed from the Bronco on June 14th, I believe on direct examination you indicated what about those?
The low numbers indicate samples that are--that were collected on that early date. The high numbers, the hundreds, those are the later samples.
All right. Now, in terms of 30 and 31, Mr. Clarke on his cross-examination of you, do you recall just pulled out this board and asked you to read the results, correct?
He didn't ask you whether you believed that the result on 31 was scientifically acceptable?
Dr. Gerdes, in light of the 1.3 appearing on the quality assurance sample 8--quality control sample 816 and the positive control, the intensities of those dots, the call that was made by DOJ, do you believe that it is scientifically acceptable, and I ask you this question to a reasonable degree of scientific certainty that makes a call that there is a contributor with a 1.3, 4 in this sample?
Absolutely not. You can't tell if that is real or not because it is on the control. These stain signals--you can't arbitrarily say it is real here and it is not real down there, (Indicating), so you can't make that call.
KEY QUOTEDo you see an inconsistency in the call with respect to the 1.3 on LAPD item 52 and the call on the 1.3 on sample 31?
What is your view of the call that was made on item 52 with respect to the 1.3 allele and the call that was made to item 31?
This just shows the subjectivity of this. In this case the 1.3 is not--is ignored in this particular time. On the other time it is counted and on the controls it is counted, so there is no scientific basis as to how you would determine one of these as real and one as not real, other than--I don't know how you would decide.
KEY QUOTEDr. Gerdes, if we were to assume that the 1.3 is real on item no. 52, ask you to keep that assumption in mind, first question is out of all the different systems used, is the DQ-Alpha system the most sensitive?
So if--I ask you to assume that DNA on the Bundy blood drops 47, 48, 49, 50 and 52 is degrading because of bacteria.
And that 52--on sample 52, consistent with that 1.3 because the DQ-Alpha is the most sensitive system. If you assume that to be real--
Well, let us assume that DNA on item no. 53 underwent--52--underwent a process of bacterial degradation. Do you have that in mind?
Let us further assume that there was contamination with Mr. Simpson's reference sample on June 14th at the LAPD laboratory. Do you have that in mind?
All right. In theory, if that 1.3 is real, could that represent the contribution of the original source on sample 152 which had degraded?
Once you've accidentally or some other way transferred that DNA from one sample to another, it doesn't matter how many gene systems, how many different labs, it is always going to transfer, it is always going to type as the DNA that was transferred.
It doesn't seem to make sense to me that you should see about the same level of degradation and in fact on 117, which is an older sample, should have more degradation.
Absolutely not. You can't tell if that is real or not because it is on the control. These stain signals--you can't arbitrarily say it is real here and it is not real down there, so you can't make that call.
This just shows the subjectivity of this. In this case the 1.3 is not--is ignored in this particular time. On the other time it is counted and on the controls it is counted, so there is no scientific basis as to how you would determine one of these as real and one as not real.