All right. Dr. Cotton, referring you to the board that has been marked People's exhibit 259, in particular item 47, "first drop by the victims at Bundy."
Did you in fact calculate an estimate of the rarity of individuals having the characteristics or those genetic marker types at the six markers, DQ-Alpha plus the polymarkers, and Mr. Simpson?
Did they present you with--I'm sorry, let me rephrase. Did you then obtain estimates that ranged for a low for one group, whatever that group may be, to a high for another group, whatever remaining group that is?
Can you describe for us, with regard to this evidence item, approximately how rare those characteristics are that are shared by that bloodstain and Mr. Simpson and start with whatever group it would be easier to and tell us that approximation. Does that make any sense?
The most common would be for African Americans and that would be one in 5000--approximately 5200.
The next most common would be Hispanic and that figure would be that that set of types was found in approximately one in every 32,000 Hispanics.
For these set of characteristics, the most rare frequency that we determined was for Caucasians and it would be one in 56,000.
All right. Dr. Cotton, with the Court's permission, I'm going to ask you to write to the far right of item 47 under the column marked "frequency," and start with the most common estimate in terms of the racial group wherein these characteristics are most common, and if you would write that number, then write in the word, "to" just to indicate the range and then the least common or rarest estimate calculation that you just provided.
And I have a red pen if that would help. Is that diagram low enough for you to write on?
It may not be steady enough. Mr. Fairtlough, do you want to hold on to that, please.
All right. Dr. Cotton, we will move a little faster with the succeeding ones, but I want to ask you a couple of questions first. When you have provided this range from one in 5200 people to one in 56,000 people, is that simply an estimate across these three racial groups of approximately how common or rare these DNA types are that are shared by this bloodstain and Mr. Simpson?
Drawing your attention to item no. 48, the Bundy walkway, first of all, were those results, as far as the DQ-Alpha and polymarker is concerned, the same as item 47?
All right. All right. And perhaps we can make this a little faster. Is that also true to the other Bundy walk stains as far as PCR testing is concerned, items no. 49, 50 and 52?
All right. What I'm going to ask you to do then, Dr. Cotton, is as to those four items, the Bundy walk stains, 48, 49, 50 and 52, would you again please write those frequencies in the appropriate boxes for your PCR testing at Cellmark.
And on 52, if you could wait just a moment, I believe there is two rows there and I believe it would be the lower row for PCR. Your Honor, may we remove that marker?
Thank you, Dr. Cotton. As to these PCR results, if any of these stains were also tested at an additional marker, after using PCR, and that marker was independent of the six that you tested at Cellmark, if those characteristics matched Mr. Simpson, would the estimate be rarer?
If you take these figures and you add in yet another genetic marker, you are going to be multiplying some frequency which will be less than one, and then taking the inverse, which is how you get the one in some number, and that will mean--it will of necessity make these numbers more rare.
Turning your attention again to the Bundy stain, item no. 52, did you also calculate an estimate of the frequency for the RFLP matching characteristics to Mr. Simpson at five different probes?
Did that also--or have you also reported an estimate across these three different racial or ethnic groups?
All right. Could you describe, first orally, in what group those characteristics were most common?
The RFLP pattern from item 52, when that was used to calculate a frequency, the frequency that is calculated for African Americans and Caucasians is the same and those estimations are that that set of characteristics would occur in approximately one in 170 million individuals. The frequency for western Hispanics is more rare than that and that frequency is that that same set of RFLP characteristics would occur in approximately one in 1.2 billion.
Now, as far as that estimate for African Americans and Caucasians, does that mean that that characteristics Mr. Simpson has that are also found in the Bundy walk bloodstain are only found in approximately one out of 170 million Caucasians or African Americans?
All right. If you would then with that stain, and there is a little box just above the last PCR box you wrote in that will describe RFLP, could you write in that range, the high and the low.
Dr. Cotton, the difference in the numbers between those estimates provided by PCR and the estimates that you have just provided as a result of the RFLP matches with Mr. Simpson seem to be quite a bit different mathematically; is that right?
The RFLP markers have a much, much greater level of variation in the population than the PCR markers. If you had to make them sort of in order, the RFLP markers would be at one end of the continuum, then you would sort of move down a ways and you would see DQ-Alpha and then you would move down yet further, and if you looked at the individual markers that are part of the polymarker system, they are not very informative individually, that is why you use them as a group of five, so the RFLP is--is much more discriminating of a test in terms of separating human beings one from the other.
KEY QUOTENow, let's turn, if we can, to the shoe prints, no. 56, and that included results at both DQ-Alpha and the five polymarkers, correct?
That is just what I was going to ask next. As far as the DQ-Alpha result that is written in, those were the types you observed on the shoeprint, 1.1, 1.1, correct, as far as actual types that were detected?
Now, because there was no C dot or control dot, do you use that result for DQ-Alpha in calculating an approximate or estimate of the frequencies of individuals who have those polymarker or DQ-Alpha characteristics?
No. We did not include it in the calculation of the frequency. We only used the information from the polymarker where we did get an appropriate control dot.
Is that to ensure that when you provide these estimates you are only doing it for markers and tests that have worked properly?
Now, did you calculate an approximate or an estimate of the frequency of the polymarker characteristics that are shared by the shoeprint and Nicole Brown?
Okay. For that set of types for the polymarker, the most common frequency was in Caucasians and that number was one in 48. The middle frequency was that for Hispanics and that number was one in 110. And the rarest frequency of that group was for African Americans and that was one in 610. And these again--whenever I say one in something, if I don't say "approximately" one in something, I should be. That is what I mean to be saying.
In other words, you are not offering or your laboratory doesn't offer that when an estimate is made of one out of a hundred, let's say, that if one examined a hundred people one would find one person with these characteristics, went to another group and out of a hundred would find these characteristics once and only once?
That is the--what the probability is. Telling you in reality it might be slightly different than that. You might find two in a hundred or none in a hundred.
All right. Could you then, with respect to the shoeprint, then write in those frequency ranges that you just described.
All right. Let's turn now then to 84-a, the left nail clippings and scrapings, and you described the fact that at the DQ-Alpha marker and polymarkers, that those characteristics were consistent with Nicole Brown?
And these are estimates that you made based on your DQ-Alpha results and polymarker results?
In other words, 84-a, as well as the two samples from 84-b, the right hand nail clippings and scrapings, your laboratory obtained the same results for all three?
The most common figure for that combination of types is one in--approximately one in 2500. The middle range frequency comes out to be the one for Hispanics and that is approximately one in 7300. And the most rare comes out to be the one for African Americans for this combination and that is one in 26,000.
Could you then, in the three locations for item no. 48, the fingernails and clippings--fingernail clippings and scrapings, could you write in that range in the three locations under "frequency."
Thank you, Dr. Cotton. Now, why is there a difference in these estimates between that of the shoeprint no. 56 which matched Nicole Brown, and the estimates for the fingernail clippings and scrapings that also matched Nicole Brown?
The difference is that for the fingernail clippings and scrapings, that information includes the DQ-Alpha frequencies, and for the shoeprint, that does not.
If the shoeprint control dot had appeared properly and the types had shown, as they appeared to you, even without the control dot, would the estimated frequency for the shoeprint then be the same as that for the fingernail clippings and scrapings?
In any event, the DQ-Alpha, the fact that there was no result on the shoeprint is what makes these frequencies different?
All right. Your Honor, at this time I would like to turn to what's been marked People's exhibit 261, the Rockingham results.
Dr. Cotton, if you would, and I'm referring you to what is the Rockingham driveway stain, item no. 7.
Did you calculate a frequency for those characteristics that are consistent with Mr. Simpson from that bloodstain?
And was that for polymarker alone because of the absence of a C dot on the DQ-Alpha results?
The estimates range from the most common being for African Americans, approximately one in 410. The middle range happens to be in this case for Hispanics with one in 1500, 1500. And the most rare comes out to be for Caucasians and that is approximately one in 3400.
And then as to the last result on this board, referring you to the stain from the Rockingham foyer, no. 12, you obtained both RFLP and PCR results, correct?
As far as this five-probe match using the RFLP technique, did you calculate an estimate of the approximate rarity of those characteristics that match Mr. Simpson using RFLP typing?
Would that be the same or different from the earlier results from the Bundy crime scene, item no. 52, at which Mr. Simpson matched that Bundy stain as well?
Now, Dr. Cotton, you have written in as to the estimations of how rare these matching characteristics are between the bloodstain from the Rockingham foyer that matches Mr. Simpson as between approximately one in 170 million and one in 1.2 billion; is that right?
And is that the same result again in terms of these estimates as the bloodstain no. 52 at Bundy?
Now, did you also perform PCR typing on this same Rockingham foyer stain and estimated how rare those characteristics are that are shared with Mr. Simpson?
All right. Could you describe for us the relative rarity of these characteristics that are consistent with Mr. Simpson using PCR typing?
Those results come out to be the most common frequency for that group of types is in African Americans and that figure is approximately one in 5200. The mid-range frequency comes out to be the one for Hispanics and that is approximately one in 32,000. And the most rare frequency for that group of types comes ought to be the one for Caucasians and that is one in 56,000.
Now, are these estimates the same as with the Bundy crime scene estimate stains that were consistent with Mr. Simpson using PCR?
All right. Could you then go ahead and write those numbers under the PCR portion of item no. 12, the Rockingham foyer stains.
Now, lastly, Dr. Cotton, what I'm going to ask is that the last result board be used, which is People's exhibit 262, and I'm going to refer you to the one result or one evidence item, rather, that you've described earlier, the socks.
Do you have in the material before you your approximations of how common or how rare the matching characteristics are shared by the sock and Nicole Brown?
With respect to your RFLP typing and the five-probe match, can you describe for the jury, please, approximately how rare those characteristics are shared by the sock and Nicole Brown?
The most common being the approximation for western Hispanics and that is one in 6.8 billion. The mid-range figure is for Caucasians and that number is approximately one in 9.7 billion. And the figure that would be most rare is for African Americans and that number is one in 530 billion.
KEY QUOTEAll right. Dr. Cotton, could you on the board, in referring to again the exhibit People's exhibit 262, write in that range for the five-probe match between Nicole Brown and the sock.
All right. Dr. Cotton, you have written in under frequencies one in 6.8 billion, one in 530 billion; is that right?
Well, I don't personally know, but the figure I've been quoted is about five billion, I think.
Did you also calculate a frequency, just based on your PCR typing, of the sock as well?
Based on the PCR types alone, the figures come out as follows: The most common is for Caucasians and that figure is one in approximately 2500. Mid-range frequency is for Hispanics and that number is one in approximately 7300. And the most rare type comes out to be the one for African Americans, and that is approximately one in 26,000.
Are these the same estimates on the earlier sample using PCR that were consistent with Nicole Brown, such as the fingernails?
All right. And lastly, could you just write those numbers under "PCR" for the sock.
And again these were six different genetic markers using PCR and the five markers used to type this sample using the RFLP process?
Ladies and gentlemen, we are going to take our recess for the morning session. Please remember all my admonitions to you. Do not discuss this case among yourselves, don't form any opinions about the case, don't conduct any deliberations until the matter has been submitted to you, do not allow anybody to communicate with you with regard to the case. We will stand in recess until one o'clock.
The most common being the approximation for western Hispanics and that is one in 6.8 billion. The mid-range figure is for Caucasians and that number is approximately one in 9.7 billion. And the figure that would be most rare is for African Americans and that number is one in 530 billion.
How many people are on earth?
The RFLP markers have a much, much greater level of variation in the population than the PCR markers... the RFLP is much more discriminating of a test in terms of separating human beings one from the other.
The frequency that is calculated for African Americans and Caucasians is the same and those estimations are that that set of characteristics would occur in approximately one in 170 million individuals. The frequency for western Hispanics is more rare than that and that frequency is that that same set of RFLP characteristics would occur in approximately one in 1.2 billion.