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[cynic]

I'm going to perhaps only confuse the matter further by bumbling through this, but here goes....

Long ago I was reading that the issue of markers being unreliable arises with weak and degraded samples. The word I'm looking for escapes me this minute....

I'm specifically thinking of some research done on false positives? Or is it some other term?

Stochastic artifacts.
There are a number of things that can happen to make the interpretation of a profile difficult.
I could explain it, but I would rather you heard it from Dr Krane.

[ame="http://www.youtube.com/watch?v=p5ErDtXV-NE"]Artifacts and noise in DNA profiling (HD version) - YouTube[/ame]

As best as I could understand it, perhaps it was a weaker "peak", with the inclusion questionable when it wasn't a marker at all. I do remember that the problem comes down to different interpretation or validation of the allele by different lab techs processing them?

One of several things that I didn’t have an opportunity to get to on the show was that very issue.
I was going to quote the following and have Dr Krane comment on it.
We took a mixed sample of DNA evidence from an actual crime scene- a gang rape committed in Georgia, US- which helped to convict a man called Kerry Robinson, who is currently in prison. We presented it, and Robinson's DNA profile, to 17 experienced analysts working in the same accredited government lab in the US, without any contextual information that might bias their judgment.
In the original case, two analysts from the Georgia Bureau of Investigation concluded that Robinson "could not be excluded" from the crime scene sample, based on his DNA profile. (A second man convicted of the same crime also testified that Robinson was an assailant, in return for a lesser jail term.) Each of our 17 analysts independently examined the profiles from the DNA mixture, the victim's profile and those of two other suspects and was asked to judge whether the suspects' profiles could be "excluded", "cannot be excluded" or whether the results were "inconclusive".
If DNA analysis were totally objective, then all 17 analysts should reach the same conclusion. However, we found that just one agreed with the original judgement that Robinson "cannot be excluded". Four analysts said the evidence was inconclusive and 12 said he could be excluded.
http://www.newscientist.com/article...-dna-evidence-can-mean-prison-or-freedom.html

Sorry I can't be more clear, but I do believe this is similar to what Dr. Krane was alluding to when he spoke of statistical validation being impossible at this time based on "drop-out": if the markers are not reliable, if they're open to differing interpretations as to whether they even are an allele at a specific locus or a false positive, then there is no way to determine the accuracy of the profile.

Mixture analysis is what makes for a “bad day at the office” when dealing with profiles.
If there is allelic drop-out then the result will be, at best, inconclusive.
There was to be discussion about mixture analysis on the show, but as with the previous point, time was an issue.
This is the video by Dr. Krane that talks about mixture analysis including the problem of drop out.

[ame="http://www.youtube.com/watch?v=wVHo1Pjf210"]Statistical weights of mixed DNA profiles (HD version) - YouTube[/ame]

 

[BBB167893]

Oh, puhlleeze, BB01!! Let's not even consider that old song and dance. Plenty of information in the public domain to be used by anyone who seeks the answer to that question. I formed my opinion by using it, and I'm sure you're smart enough to decide for yourself what you will or will not consider case evidence.

Let me sharpen up, and I'll take a whack at it!

 

[BBB167893]

These last few months have been really exciting. Recap:

1) We found out the GJ DID vote to indict;

2) We have a DNA expert shooting down IDI's house of cards like a blimp over Pyongyang;

3) And it looks like my book will be out by Christmas.

I'm 3 for 3!

 

[KoldKase]

These last few months have been really exciting. Recap:

1) We found out the GJ DID vote to indict;

2) We have a DNA expert shooting down IDI's house of cards like a blimp over Pyongyang;

3) And it looks like my book will be out by Christmas.

I'm 3 for 3!

Woohoo!

Where have you been, SuperDave?! We've missed you terribly! :seeya:

Look forward to your book!

 

[KoldKase]

Stochastic artifacts.
There are a number of things that can happen to make the interpretation of a profile difficult.
I could explain it, but I would rather you heard it from Dr Krane.

Artifacts and noise in DNA profiling (HD version) - YouTube


One of several things that I didn’t have an opportunity to get to on the show was that very issue.
I was going to quote the following and have Dr Krane comment on it.
We took a mixed sample of DNA evidence from an actual crime scene- a gang rape committed in Georgia, US- which helped to convict a man called Kerry Robinson, who is currently in prison. We presented it, and Robinson's DNA profile, to 17 experienced analysts working in the same accredited government lab in the US, without any contextual information that might bias their judgment.
In the original case, two analysts from the Georgia Bureau of Investigation concluded that Robinson "could not be excluded" from the crime scene sample, based on his DNA profile. (A second man convicted of the same crime also testified that Robinson was an assailant, in return for a lesser jail term.) Each of our 17 analysts independently examined the profiles from the DNA mixture, the victim's profile and those of two other suspects and was asked to judge whether the suspects' profiles could be "excluded", "cannot be excluded" or whether the results were "inconclusive".
If DNA analysis were totally objective, then all 17 analysts should reach the same conclusion. However, we found that just one agreed with the original judgement that Robinson "cannot be excluded". Four analysts said the evidence was inconclusive and 12 said he could be excluded.
http://www.newscientist.com/article...-dna-evidence-can-mean-prison-or-freedom.html

Mixture analysis is what makes for a “bad day at the office” when dealing with profiles.
If there is allelic drop-out then the result will be, at best, inconclusive.
There was to be discussion about mixture analysis on the show, but as with the previous point, time was an issue.
This is the video by Dr. Krane that talks about mixture analysis including the problem of drop out.

Statistical weights of mixed DNA profiles (HD version) - YouTube

Thanks for your answers and the video, cynic. I plan on typing up some of the blog radio interview, so after that I'll take a stab about these.

Stochastic artifacts; locus, loci; alleles, allelic...let's call the whole thing off! :facepalm:

 

[BBB167893]

Woohoo!

Where have you been, SuperDave?! We've missed you terribly! :seeya:

Look forward to your book!

Oh, I've been creeping around, doing my thing wherever it's needed.

 

[KoldKase]

John found the body at 11 am.
Patsy dressed JonBenet's body after wiping it and tranfered the fibers.

Let me guess: Prime of Miss Jean Brodie and religious ritual? Where, oh where, have I heard this theory before?

Signed,

A Has-been

 

[midwest mama]

Let me guess: Prime of Miss Jean Brodie and religious ritual? Where, oh where, have I heard this theory before?

Signed,

A Has-been

Maybe from a breeze whisper - during one evening while enjoying a libation under a starry sky gently lit by the reflection from the face of the Man in the MOON?

 

[cynic]

Transcript of Dr. Dan Krane’s DNA info related to the JBR case: Tricia’s radio blogcast, Sunday, August 18, 2013
http://www.blogtalkradio.com/websleuths/2013/08/19/tricias-true-crime-radio-sunday-night-8-pm-eastern
(Special thanks to KoldKase for her help with the transcript.)

Dr. Krane’s website:
http://www.bioforensics.com/

Dr. Krane’s CV:
http://www.bioforensics.com/CV/KraneCV01-12.pdf

The following begins at 52:30 and extends to the end of the show segment with Dr. Krane

Cynic: I cannot let you go, Dr Krane, without your thoughts regarding the DNA evidence in the JonBenet case. I know that when we spoke, and when we emailed one another, you made some interesting comments that need to be said, so I’m going to give people a real quick lead-in and then let you take it away.
I don’t want to get into the minutia of the DNA case primarily because I don’t have the time, but I would like to focus on the DNA that’s been in the mainstream media for many years with respect to the JonBenet case.
One area in the crotch of JonBenet’s underpants that was tested revealed a profile that was ultimately uploaded to the FBI database, CODIS.
JonBenet was the major donor by virtue of contributing blood, and there was an unknown minor male profile from unknown cellular material.
That minor unknown male profile was a mixed profile with drop-out because only 10 out of 13 loci were found.
In 2008 the long johns which were worn over the underpants were sent to a private lab, Bode, as I’ve already touched on before, and they did razor scraping and so on, and it was publicly revealed that this testing resulted in DNA profiles which, while weaker than the CODIS profile, were considered to match.
So we know that these profiles were 9 loci or less.
There are, of course, a number of possible transfer mechanisms between two articles of clothing, one worn tightly over the other, you know, it could have been transfer based on that.
It could have been something that happened perhaps at the autopsy, perhaps proper safeguards weren’t in place.
Things were touched, even with gloves, it doesn’t matter, if you’re touching certain evidentiary items if you touch others without changing your gloves it’s possible that that could be a source of contamination.
Even the coroner or medical examiner, if handling instruments that weren’t properly cleaned, could have transferred from previous autopsies, and so on; there’s just a number of ways, as we’ve touched on throughout this broadcast in terms of transferring DNA evidence.
I would like to focus, however, on the fact that this was a mixed sample with drop-out-- and by drop-out I mean we don’t have information at all of the loci. For example, if I were to take a swab, a cheek swab, and send it to the lab I would have all thirteen of the CODIS loci light up and there would be a full profile.
These are partial profiles, also mixed; at least we know for a fact that the blood spot was mixed because it primarily had JonBenet’s blood.
You’ve made the statement, and it’s one that I’ve actually never heard before. You’ve told me that there is no generally accepted means of attaching a reliable statistical weight to a mixed DNA profile where allelic drop out may have occurred. You then went on to tell me that, essentially what this means is that, in your opinion, from the evidence that I sent you that this DNA evidence really could not be presented in court. Could you comment?
Dr Krane: I’m sad that you hadn’t heard that before because that means that we’re not doing a good enough job of getting the word out, and often a big part of my job when I get involved with a case is educating attorneys and educating juries about things like that: that at the present time there is no generally accepted means of attaching a statistical weight to a mixed DNA profile where drop-out may have occurred. In other words, we’re getting partial or incomplete information about one of the contributors.
Now, in an unmixed sample, we can deal with drop-out; but in a mixed sample, I don’t think we have the time for me to explain to you the underlying reasoning behind it, but it’s just not possible for us at the present time. It’s not for lack of trying.
At the Forensic Science Service (based in the UK), before it went out of business a few years ago, had invested millions of pounds into solving this problem. There are some people now starting to say that there might be some way to attach weight to those kinds of samples. But here’s what it all comes down to: there’s an abundance of case law within the United States that says that if you can’t attach a statistical weight to a DNA inclusion, saying that someone matches an evidence sample, if you can’t put a number on that--one in a million, one in a quintillion, something like that-- you can’t admit it as evidence. It is not something that can be presented to a jury because they simply won’t know what weight to give it if you can’t attach a reliable statistical weight. So, absent a statistical weight all that can really be said is, about a mixed sample where drop-out might have occurred, is that the test results are inconclusive. We simply are in no better position to say if an individual has contributed to a profile or not, relative to where we were before the test or after the test was performed.
So, the samples that you’re talking about here, the blood stain in the JonBenet Ramsey case from the crotch of the panties, I think at the end of the day that’s simply not something that could be presented to a jury. Now it could be used to generate investigative leads, law enforcement could use Ouija boards to generate investigative leads if they like…
Tricia: Exactly, there you go.
Dr Krane: …but it’s not something that you could talk about in court.
Tricia: Exactly.
Cynic: Tricia, this is concerning Mary Lacy, our “friend,” so I would be remiss if I let Dan go without this real quick point.
We also spoke about this:
The District Attorney went from saying this in 2006: "The DNA could be an artifact. It isn’t necessarily the killer’s… “
To, in 2008, saying: “Unexplained DNA on the victim of a crime is powerful evidence. The match of male DNA on two separate items of clothing worn by the victim at the time of the murder makes it clear to us that an unknown male handled these items. Despite substantial efforts over the years to identify the source of this DNA, there is no innocent explanation for its incriminating presence at three sites on these two different items of clothing that JonBenet was wearing at the time of her murder.”
When you and I talked I just asked you as a hypothetical, if a District Attorney is, for example, exonerating people that were suspects for many years based exclusively on the DNA that we’ve just discussed here, is that an overreach?
Dr Krane: Well, let me draw particular attention to the word, “exclusively”: right, if that is the sole basis for the decision, I think that conveys a lack of understanding of what’s involved with those particular types of DNA test results.
Tricia: Thank you, perfect, keep going – I just wanted to hear that. That’s exactly what we wanted to hear. Please continue and we’ll wrap it up.
Dr Krane: Well, I don’t know that there’s too much more to say. It’s an overreach in the sense that, again, we’re talking here about something that couldn’t be presented to a jury and it’s an overreach because it seems to be violating, or it has the potential to violate, that axiom that I began with: that the presence of a DNA profile doesn’t necessarily say anything about the time frame or the circumstances. We can’t say that it got there because it was deposited during the commission of a crime; we can’t say it got there because the laundry had been done in a way that got somebody else’s DNA there; or it could have come there through contamination after the evidence had been collected and handled in a lab. There’s so many different ways that the DNA could have gotten there that, that by itself, those partial profiles, that’s not something that we should be attaching that kind of weight to.

 

[KoldKase]

All I did was tweak a few punctuations for clarity because it's so subjective when transcribing interviews. As usual, cynic did all the heavy lifting.:tyou:

I do have some notes from the interview I'll add at some point, but right now I'm swimming around a jury pool, trying to avoid the reptiles. :croc:

 

[Chelly]

Cynic, KoldKase, Tricia...and of course Dr. Krane....Many, many thanks for such good and valuable work.

 

[BOESP]

Two bombshells from the show
The much vaunted DNA evidence that Mary Lacy, Lin Wood, John Ramsey and some others have shamelessly paraded around would NOT BE ADMISSIBLE in court because it is a mixed profile with dropout.
“… there is no generally accepted means of attaching a reliable statistical weight to a mixed DNA profile where allelic drop out may have occurred."
Listen at 54:38 – 58:25
Continuing on with Mary Lacy, Dr Krane said that if she based the exoneration exclusively on the DNA evidence then that was WRONG – “THAT THAT CONVEYS A LACK OF UNDERSTANDING OF DNA.”
Listen at 58:42 – 61:00

Just bumping this thread to refresh the understanding or to correct the misunderstandings about the value of the DNA in the JonBenet Ramsey case.

 

[ScarlettScarpetta]

I don't think there is a lack of understanding.. And if the samples are sent to codis as a reliable sample to match, That means it is usable.

 

[Venom]

I think what he's trying to explain is:

-the samples were sent to codis
-but the DNA couldn't be used in court because of the mixed dropout, there's no statistic used to show the mixed dropouts
-if ML exonerated the R's just by DNA alone, then that is not right as there is no statistical weight to it.

BOESP, am I right?

 

[BOESP]

I think what he's trying to explain is:

-the samples were sent to codis
-but the DNA couldn't be used in court because of the mixed dropout, there's no statistic used to show the mixed dropouts
-if ML exonerated the R's just by DNA alone, then that is not right as there is no statistical weight to it.

BOESP, am I right?

That's the way I understood it, Venom. Cynic's transcripts here are well worth taking time to read and visiting Dr. Krane's links are informative.

Here is a direct quote from Dr. Krane, as shown above:

"So, the samples that you’re talking about here, the blood stain in the JonBenet Ramsey case from the crotch of the panties, I think at the end of the day that’s simply not something that could be presented to a jury. Now it could be used to generate investigative leads, law enforcement could use Ouija boards to generate investigative leads if they like… "

I like Dr. Krane's style. :dance:

 

[ScarlettScarpetta]

I think what he's trying to explain is:

-the samples were sent to codis
-but the DNA couldn't be used in court because of the mixed dropout, there's no statistic used to show the mixed dropouts
-if ML exonerated the R's just by DNA alone, then that is not right as there is no statistical weight to it.

BOESP, am I right?

I doubt that is true now. If it is enough for CODIS to get a hit, there is no reason that that would not be used in court as the method of which the perp was identified.

 

[Venom]

It couldn't be used in court because there is no statistical weight to it due to the mixed dropouts.

Dr Krane: "Well, I don’t know that there’s too much more to say. It’s an overreach in the sense that, again, we’re talking here about something that couldn’t be presented to a jury and it’s an overreach because it seems to be violating, or it has the potential to violate, that axiom that I began with: that the presence of a DNA profile doesn’t necessarily say anything about the time frame or the circumstances. We can’t say that it got there because it was deposited during the commission of a crime; we can’t say it got there because the laundry had been done in a way that got somebody else’s DNA there; or it could have come there through contamination after the evidence had been collected and handled in a lab. There’s so many different ways that the DNA could have gotten there that, that by itself, those partial profiles, that’s not something that we should be attaching that kind of weight to."

 

[ScarlettScarpetta]

It couldn't be used in court because there is no statistical weight to it due to the mixed dropouts.

Dr Krane: "Well, I don’t know that there’s too much more to say. It’s an overreach in the sense that, again, we’re talking here about something that couldn’t be presented to a jury and it’s an overreach because it seems to be violating, or it has the potential to violate, that axiom that I began with: that the presence of a DNA profile doesn’t necessarily say anything about the time frame or the circumstances. We can’t say that it got there because it was deposited during the commission of a crime; we can’t say it got there because the laundry had been done in a way that got somebody else’s DNA there; or it could have come there through contamination after the evidence had been collected and handled in a lab. There’s so many different ways that the DNA could have gotten there that, that by itself, those partial profiles, that’s not something that we should be attaching that kind of weight to."

That makes no sense. If it is enough to identify the suspect. Enough to link to them, and now they even have new access to more material from the suspect, I don't doubt it would be used in court.

If there was not enough to put in CODIS I could understand that. But if they can identify someone definitively from the sample in CODIS, That is going to get brought up in court.

 

[ScarlettScarpetta]

A: CODIS was designed to compare a target DNA record against the DNA records contained in the database. Once a match is identified by the CODIS software, the laboratories involved in the match exchange information to verify the match and establish coordination between their two agencies. The match of the forensic DNA record against the DNA record in the database may be used to establish probable cause to obtain an evidentiary DNA sample from the suspect. The law enforcement agency can use this documentation to obtain a court order authorizing the collection of a known biological reference sample from the offender. The casework laboratory can then perform a DNA analysis on the known biological sample so that this analysis can be presented as evidence in court.

http://www.fbi.gov/about-us/lab/biometric-analysis/codis/codis-and-ndis-fact-sheet

 

[Venom]

Yes. I understand that and did read that page just the other day.

The problem lays with the dna sample being a mixed profile with dropout not being acceptable in court.