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Zimmerman Trial Coverage Continues; Crime Lab Analyst Testifies
Aired July 3, 2013 - 14:00 ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
ANTHONY GORGONE, CRIME LABORATORY ANALYST: And it's the genetic blueprint that makes each person unique. It codes for everything about you. Everything from the pigment making up your eye color, to the enzymes in your stomach breaking up your lunch right now.
BERNIE DE LA BIONDA, PROSECUTOR: And how is DNA used in a forensic setting?
GORGONE: Forensically, your DNA is found -- a copy of your DNA is found in almost every cell in your body, therefore it can be left behind in bodily fluids that you leave behind, such as blood, semen, saliva, almost sometimes hair and skin cells as well. And forensically, I could use those bodily fluids to develop what I call a DNA profile, which would be to analyze the DNA at certain locations on the DNA molecule, develop a DNA profile that could be used for identification purposes and comparison.
DE LA BIONDA: Is -- are there other uses for this technology other than in a forensic or criminal setting?
GORGONE: Yes. Several fields use DNA. The same DNA testing that I use. It's used in medical and genetic research. It's used in organ and blood transplant donor recipient evaluations. It's used to test the - to test any abnormalities in the fetus during pregnancy when they do the amniocentesis. It's used in the identification of mass disaster victims, as well as the Innocence Project and paternity testing as well.
DE LA BIONDA: Is the DNA profiling comparison method using STR, that you're going to talk about that your lab uses, being accepted in the scientific community as being reliable?
GORGONE: Yes, it is.
DE LA BIONDA: And is your lab, FDLE, been accredited and been through all the hoops in terms of their accreditations or being findings that they're proficient, et cetera?
GORGONE: Yes, we are an accredited laboratory.
DE LA BIONDA: OK. I want to talk about the laboratory procedures for a few minutes, if we could. Do you all have an established protocol or methods in which an item comes into your lab where you make sure that there's no contamination and that kind of stuff? GORGONE: Yes. We have a quality assurance program that says that we have documentation of all the quality procedures. We have standard operating procedures that give specific instructions for every test that I do so that every person working in the lab is on the same page and one person isn't doing one thing their way and another person doing another thing their way. So we have written protocols and all of our quality assurance program is in writing.
DE LA BIONDA: In -- are there any controls within the testing themselves in terms of positive and negative controls to verify that what you're doing is accurate in terms of not getting any misidentification or contamination?
GORGONE: Yes. There are positive and negative controls at just about every step of the way. Before I even do the DNA testing, if I'm screening for the possible presence of blood, I need to test a positive control and a negative control of blood to make sure the chemicals I'm using are working. During the DNA testing, I have positive controls where I have a DNA profile I need to get that expected DNA profile at the end of the process to know that not only that the chemicals and the instruments are working, but that my techniques are good as well. There are also negative controls at a few steps during the way and those would be blank samples and those samples need to remain blank the entire process.
DE LA BIONDA: In the lab while you're analyzing evidence that's submitted in the lab, do you wear any kind of clothing attire to make sure that you don't cross-contaminate anything?
GORGONE: Yes. Whenever I have an item of evidence open and I'm physically examining that item, I'm required to wear a lab coat, a mask, gloves and sometimes a hair net depending on the item. When I'm actually working with the tubes and actually doing the DNA testing process, I'm also required to wear a lab coat and mask and work in chemical hoods with a -- it's a sash that covers in front of my face.
DE LA BIONDA: And are all these procedures for quality control methods that you all utilize at FDLE, are they used by other labs in terms of being accredited?
GORGONE: Yes. Any lab with a quality assurance program in place is going to have very similar protocols as far as quality control.
DE LA BIONDA: Tell us if you could briefly about proficiency testing in terms of testing yourself and also your lab to make sure that what you all are doing is working properly.
GORGONE: A proficiency test is a test given to me by an outside company. It's mailed in and it's a set of samples that I have to work as if it were a regular case. And I perform that testing and send the results back to that company. And then they send a notice back saying, yes, you got the correct results or, no, you did not get the correct results.
I'm required to take a proficiency test every six months. So I take one about May and about November of every year. And I've done that every -- every year that I've been doing independent case work, since August of 2008.
DE LA BIONDA: And is the lab -- the entire lab also subject to proficiency testing, the DNA lab, or the lab but the DNA department of the lab also?
GORGONE: Yes. Everyone -- every crime lab analyst, and even the forensic technologists, have to go through some kind of proficiency test twice a year.
DE LA BIONDA: OK. Let's briefly talk about the exhibits themselves that would be tenured into your lab for analysis. In terms of making sure that you have the right exhibit in front of you when you're analyzing it, what kind of quality controls do you all have? Is there some numbering system or some cataloging of the items when they come in?
GORGONE: When an item is submitted for testing, we get items from outside agencies such as local law enforcement agencies in the central Florida area. They submit the items to our evidence intake section. The evidence intake section makes sure that that item is in a sealed condition. And they issue it an exhibit number for the Florida Department of Law Enforcement exhibit number and put a barcode label and a case number on it. And then that item gets brought up to me, once I'm assigned the case, and then I - I also examine that item to make sure it's in a sealed condition and we have that barcode label, the Florida Department Law Enforcement case number and exhibit number.
DE LA BIONDA: Do you also document when you analyze something in terms of putting your initials or some kind of markings to be able to say, like, you will have to here in court and say, yes, I know I examined this item?
GORGONE: Yes. I mark the package that I -- before I open the package, I mark that package with my initials, the Florida Department of Law Enforcement case number exhibit, and the date that I'm examining that item. And then the actual item itself, unless there's a reason why I can't mark that item, I will mark that item as well with that same information.
DE LA BIONDA: OK. Let's now move on to the DNA testing you did in this specific case. I believe you used STR DNA testing, is that correct?
DE LA BIONDA: OK. Tell us when we talk about STR DNA testing, what we mean by that, or what you mean by that, I should say.
GORGONE: STR testing is called - is Short Tandem Repeat testing. And it's -- I'm analyzing short segments on the DNA molecule that are highly repetitive segments. They don't actually code for any physical characteristic or any kind of molecule inside your body that's doing a job. They are just repetitive, noncoding regions of DNA. And I can take advantage of that fact, the fact that those repetitive sequences vary from individual to individual. So I can use these short segments of DNA to develop a profile for that individual. DE LA BIONDA: And if you could, I'd like you to break down the -- in terms of the STR process, are there, I think, three or four steps that you have to go through in order to first determine whether you have enough DNA to actually develop it?
GORGONE: Yes. Well, the first step would obviously be analyzing the item of evidence for the possible bodily fluids, the blood, semen, saliva, as well as hair and skin cells. Once I had that stain that I want to perform DNA testing on, I take a small portion of that stain, or a swab, and put it in a tube and use heat and chemicals to perform what I call an extraction. That breaks open the cells in that stain, exposes the DNA molecule, and then hopefully I can isolate that molecule and wash away all of the debris and all of the other chemicals in that sample.
The next step would be called quantification, where I take that sample and see about how concentrated, about how much DNA was I able to recover from that stain. And I used that information for the next step, which is amplification. I'm basically making Xerox copies, almost, of the DNA molecule, but only at these 13 or 15 different regions that I'm interested in testing to develop the DNA profile. I make millions and millions of copies of the molecule at these specific regions so that I can analyze these regions.
The last step is called electrophoresis, where I actually separate out the DNA molecules that I was able to amplify by size. I get a data readout. I interpret that and create the DNA profile, which is essentially a set of numbers. And I can use those numbers for comparison.
DE LA BIONDA: And when you're going -- I'm sorry. You need a minute?
DE LA BIONDA: I'm sorry. When you're going through the extraction process, the stain, or what you believe is a stain, might you be given the actual exhibit itself? Like if I gave you this pen, or may they be a swab from that pen that you're first looking at?
GORGONE: It varies. Sometimes I get an actual item, like a pen, and say, who was possibly handling this pen. And then I have to take a swab and swab that pen for any skin cells that might be left behind. Sometimes I get a swab that was collected from an item and it was collected by the agency that submitted that, say Sanford Police Department or Orlando Police Department. They swabbed the pen themselves, put that swab in a box and sent that box in to be tested. So then I just have the swab to work with. I take a cutting of that swab with a scalpel, put that in a tube to perform my testing.
DE LA BIONDA: In terms of that second step you talked about, the quantification, you need a certain amount of DNA in order to - even get a result. And what's the minimum you need?
GORGONE: Well, there's really no minimum. That step tells me about how much DNA I have in the sample. And I use that information for the amplification step. The amplification step, it's kind of like a recipe. If you have a recipe that calls for one cup of sugar, ideally this recipe calls for about one nanogram or 1.5 nanograms of DNA. So I'd like to have that 1.5 or 1 nanogram of DNA to put in that tube in order for the reaction to work right for me to get a DNA profile that I can use for some kind of comparison.
But if I have less than that, I'm still going to go through with the rest of the steps to see because sometimes I can get less information than the full, complete DNA profile but it's still enough for me to make comparisons. And then there's plenty of times where I don't have enough DNA and I don't get any results or I get very little results. But I still go through with the step. There really is no minimum or I look and say, OK, I don't have enough DNA there, I need to stop. I'm going to go through with it regardless of how much DNA I have in that sample.
DE LA BIONDA: And educate us if you could, nanogram, what is that? What's - how much is that?
GORGONE: A nanogram, it's a very small amount. If you basically - if you take an index card and cut that index card up into a million pieces, that would be about a nanogram, I believe. It's not a quantity that you can touch or feel.
DE LA BIONDA: Now you mentioned also that in the process you're looking for markers or (INAUDIBLE) and you mentioned that the test you do is either going to give you 13 or 15 possible, is that correct?
DE LA BIONDA: OK. In terms of STR, you have 13 or 15? Did I get that right, in terms of markers?
DE LA BIONDA: OK. Do you always get 13 or 15?
GORGONE: No. Like I said, sometimes, based on the sample, the amount of DNA I have or the condition of the DNA, sometimes I get less than the full amount of locations that I'm testing. That would be called a partial DNA profile.
DE LA BIONDA: And if you get a partial DNA profile, are you still in certain cases --
BROOKE BALDWIN, CNN ANCHOR: This is fascinating. This is the science talking quantification and molecules. Bottom line, this is a crime scene technician, an analyst, an expert, really. And what we're waiting for, what we're going to hear are questions specifically about Trayvon Martin's DNA and blood, where that landed, and also that of George Zimmerman. Is there any DNA from Trayvon Martin on Zimmerman's gun? A quick break. Be right back.
BALDWIN: We'll take you back to Sanford, Florida, in just a moment. But I have to show you these pictures. Look at this. Left hand side of your screen, hundreds of thousands of people protesting against the democratically elected president of Egypt Mohamed Morsi. That is Tahrir Square. That was the heart and soul of the revolution some two and a half years ago that ultimately ousted the then leader, Hosni Mubarak.
On the right side of your screen, just a couple miles away, folks with quite a different perspective. These are pro-Morsi demonstrators. According to a Morsi spokesperson that we've been in touch with here at CNN, there has been a coup in Egypt. The fact is that the military, according to this spokesperson, has taken over. According to our senior correspondent Ben Wedeman, whose there on the ground in Cairo, was reporting on our air a little while ago that Mohamed Morsi is in the Republican Guard complex, we believe. What he's doing there, we don't know. But according to witnesses, the army has erected barbed wire barriers around barracks where Mohamed Morsi is currently.
We are awaiting a statement from the military. What will they say? What is the road map for Egypt as we look ahead? We'll take you live to Cairo here momentarily.
In the meantime, back to Sanford, Florida, back to this crime scene technician talking specifically DNA and blood at this crime scene from February of last year. Here you go.
GORGONE: It's somewhere in between. I can't include them in the mixture and I can't exclude them based on what I'm seeing, so I'm not able to make any kind of determination for that person to that mixture.
DE LA BIONDA: Sometimes when you examine an exhibit, do you do a preliminary test to determine whether it's even blood?
DE LA BIONDA: Tell us about that briefly, that testing, what that involves.
GORGONE: Depending on the case scenario, when I open an item and look at it, I could be looking for any of those bodily fluids that I discussed earlier. So if I'm looking for blood and I see a red brown staining on the article of clothing or the swab or whatever it is, I'll take a rubbing of that stain, try to rub off a little of that material on to a small piece of filter paper and I apply a series of three chemicals. And if I get a pink color change at the end of that series, that would give me an indication that that would be positive for the possible presence of blood.
DE LA BIONDA: Before we get into the heart of why you're here, I want to talk briefly about the significance of your findings. Assuming you get DNA results, I want to talk briefly about the population matters. And let me just ask you some questions regarding that, if I could.
When you examine the results, let's say you get an STR test, do you then determine the probability of a match in terms of what are the probabilities you know is it -- tell us a little bit about that.
GORGONE: Yes. When I have a match, when I have a single source profile or a mixture and someone matches that DNA profile or they're included in that mixture, I need to put a relevance to that match. If I got a result at one location, at one of the 13 locations that I test, and it matches an individual, and what is the relevance of that one location matching an individual? There could be, you know, maybe three other people, four other people in this room that match that location. So I need to put a statistical relevance to that match.
So when I have 13 locations, I perform what's called a random match probability. When I have any amount of locations that I get, I perform a random match probability. And it's the possibility that you would pull a random person off the street and test their sample, and that they would match that unknown DNA profile that I got, whether it's at one location, two locations, or all 13 or 15 locations.
DE LA BIONDA: And is there a database that you have as a baseline in order to compare it to determine in terms of the percentage of the population, or what -- how likely is that to occur?
GORGONE: Yes. The different results that I could get at these locations, they aren't evenly distributed in the population. Some results are more common than others. So I use population databases that were put together for the purpose of estimating about how rare or frequent these different results are in certain ethnic groups.
DE LA BIONDA: And are you familiar with the database that you all use?
DE LA BIONDA: OK. And has that been accepted in the scientific community of being reliable in terms of -- do you use the pop (ph) stats, I believe, for FBI, or what do you use?
GORGONE: I used two different databases during the course of working this case. We used -- for years we used the FBI's population database. That is generally used within the scientific community. I did test a couple samples later on in this case where we had switched to a different database. We call that the Butler (ph) database because it was created by Dr. John Butler. And that's the one we currently use on our casework.
DE LA BIONDA: And has that been accepted in the scientific community as being reliable?
DE LA BIONDA: OK. And do you use the product rule in some way, too, in factoring that all in?
DE LA BIONDA: Tell us briefly about the product rule.
GORGONE: The product rule, it's a simple statistical concept that says, if you have a frequency for one event and a frequency for another independent event, and you want to see what's the frequency that both these events could occur at the same time, you can multiply their frequencies together.
So, for example, if you have a coin and you flip that coin, you have a 50 percent chance of heads, 50 percent chance of tails. Well, if you want to see what's the probability that I'm going to have two coins and I'm going to flip both and they'll both land on heads, you would multiply that 50 percent for one coin, 50 percent for the second coin, and you would get 25 percent that they would both land on heads.
This applies to the random match probability, the statistics I use, because these 13 or 15 locations that I test are all inherited independently. So once I determine the frequency that you would find the results at one of these locations in the population, I can then multiply it with the other 12 or the other 14 locations using this product rule to get a frequency that you would find that entire DNA profile.
DE LA BIONDA: In terms of some of the results that you're going to talk to this jury about, why are some of the results in terms of the pop -- the numbers more than the actual population of the earth? Which I believe is now 6.5 or maybe 7 billion. Why is it higher?
GORGONE: I think it's almost 7 billion now, the population of the earth. It really doesn't have anything to do with the population of the earth. It's more about the frequency at which I see these results. It's similar to, if you think about it, sometimes you see it posted somewhere that the frequency -- or the probability of winning the lottery is one in a million. Well, that doesn't have to do -- that has nothing to do with how many people play the lottery or how many people live in the area, it just has to do, what is the probability that I'm going to match all six or seven of these numbers and get them all right.
BALDWIN: A quick break. Back to Sanford, Florida, after this.
WOLF BLITZER, CNN ANCHOR: I'm Wolf Blitzer in Washington.
We're following huge breaking news out of Cairo. We expect momentarily the opposition leadership in Egypt, the opposition to the Egyptian President Mohammed Morsi, to be making a statement. What's being described as a road map to new elections in Egypt.
It looks like the Egyptian military has dramatically stepped in. Mohamed Morsi, unclear where he is, what his status is right now. He is the democratically elected president of Egypt. But clearly the Egyptian military and millions of Egyptians, they have an other idea for Morsi right now.
We're continuing to follow what's happening on the streets of Cairo, the pro and anti Morsi demonstrations that seem to be escalating right now. We're going to get that statement from the opposition leader, Mohammed el Baradei, the former head of the International Atomic Energy Agency. He's been intimately involved in working the Egyptian opposition. We expect him to be making a statement soon. We'll have live coverage of that. Stand by.
In the meantime, let's go back to Brooke. She's following the Zimmerman trial.
BALDWIN: We'll watch for that. Wolf Blitzer, thank you so much for the update on what's happening right now in Egypt.
I want to take you back now to this George Zimmerman trial underway in Sanford, Florida. Once again you see him on the stand. This is a crime lab analyst talking science and DNA.
GORGONE: The outer package has our FDLE barcode label, my initials, the date I opened the package. The internal packages with the swabs also have my initials and the date.
DE LA BIONDA: And what is that, sir?
GORGONE: This would be buccal swabs taken from George Zimmerman. That would be swabs take from the inside of the mouth.
DE LA BIONDA: OK. If I could show that to the jury, your honor.
UNIDENTIFIED FEMALE: OK, you may.
DE LA BIONDA: So all this writing that's on here in terms of - with your initials would be on here, right here, right? I got it right, where would your initials be on here?
GORGONE: Right here.
DE LA BIONDA: OK. That that would be true of all the exhibits? In other words, if you could verify that you actually did analysis on this?
DE LA BIONDA: OK. And it would have your FDLE number and I think you said the yellow quick (ph) card or whatever you call this label is also FDLE?
GORGONE: Yes, the yellow barcode label is from FDLE.
DE LA BIONDA: Now, those are what I think you referred to as standards, correct, (INAUDIBLE) standard from George Zimmerman and also from Trayvon Martin, is that correct?
GORGONE: Yes, those are known standards that were used for comparison to all the unknown samples in the case.
DE LA BIONDA: OK. You do the process. You go through the extraction, quantification, et cetera. You get some results I'm assuming, right?
DE LA BIONDA: OK. Did you get some in this case, on both of those occasions?
DE LA BIONDA: OK. Do you then prepare - and for the record, I'm going to show you state's exhibit 206, previously been shown to counsel and no objection. Well, I'll show it to you.
UNIDENTIFIED MALE: OK.
DE LA BIONDA: I'm going to show you - I'll put it on the (INAUDIBLE) -- may I approach the witness, your honor?
UNIDENTIFIED FEMALE: Yes, you may.
DE LA BIONDA: Let me actually show you the actual exhibit so you have it there, but -- and I want you to talk about this and explaining - I believe there's 13 (INAUDIBLE) markers on this one. So let me show you state's exhibit 206.
Thank you, your honor.
Tell us just, when you talk about all these markers, let's go - and you don't have your (INAUDIBLE). I need Mr. Guy's assistance. (INAUDIBLE).
May I approach the witness again, your honor?
UNIDENTIFIED FEMALE: Yes, you may.
DE LA BIONDA: I'm going to give you this fancy pen, I guess, or whatever you call it. And I think the button's right -- you see it? OK.
Let's talk about -- you got three columns here. And let's -- actually, I think I can do it here in the red, too. So you do green, I'll do red. But let's talk about this description right here. What are all these? I know they're referred to as loci (ph). What does this mean right here?
GORGONE: These -- this column right here is the -- they are the names of the 13 locations that I tested for these samples. They're -- loci (ph) is like a fancy scientific way of saying location. So I test 13 loci (ph). Loci (ph) would be plural and locus (ph) would be one single location. So these are their names. And they basically represent, you know, about where these locations are located on the DNA molecule.
DE LA BIONDA: Who came up with D3S135A (ph)? Who came up with that fancy name for that?
GORGONE: I have no idea. They're basically representing where, on what chromosome -- this would be on the chromosome 3, chromosome 8, and they represent about where on the DNA molecule that they are located. These locations that I test.
DE LA BIONDA: All right. And tell me the significance of this one right here that I'm circling.
GORGONE: The - yes. The amelojenin (ph) location is in addition to the 13 location. It's a sex determining location. And it gives me an indication of whether or not that individual has two x chromosomes, which would make them a female, or an x and a y chromosome, which would make them a male.