Why the DNA may NOT be important

[2 percent]

Actually the only ones who do not get DNA are the ones here trying to explain how in this case, the only one in history that DNA just doesn't matter.

No...I think that was the OJ jury.

 

[Anti-K]

Really? I wasn't aware this is a forum of DNA experts. I certainly would never presume to be one...maybe that's just me.

In fact I found the section: "How not to use DNA profile evidence" particularly informative, which immediately brought to mind Dr. Krane's warning when asked about the sample in this case....



Also of note from the article...

"Considering the profile in isolation..."

IMO without a match--which conceivably might never happen--or any other sign of an intruder, it needs to be considered relative to ALL the other aspects of the case. We can't ignore the fact that it's useless in a court of law as it stands right now.

It's ironic that in the example used in the article a man was convicted b/c of faulty DNA reasoning and analysis, yet he may very well have been innocent.

The article sums it up quite well...



Anyway, thanks BOESP for an interesting and easy to understand article.

Signed me: someone who always appreciates relative information

So many misunderstandings...!

Once again, Dr Krane is correct in general, but incorrect in specificity. The DNA to which he refers is the CODIS sample ONLY. And yet, this sample is a CODIS sample. CODIS does not – CANNOT – accept samples to which no statistical weight can be applied. No statistical weight means the sample is inconclusive – NO identified markers. Clearly, this is not the case with the CODIS sample.

Two factors go towards eliminating Dr Krane’s concern: one of the two samples in the mix is known – the victim’s; and, the tDNA confirms the CODIS sample results.
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"Considering the profile in isolation..." There’s no need to do this. And, we do not consider this evidence relative to all other aspects of the case, we consider it as a part of the case.
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The article cited uses an argument that was rejected by the courts and the court of appeal. The author (and, Adam’s defence) tried to use bayesion formulations to “tweak” the role of RMP. That’s nonsense, and the court recognized it as such. I can elaborate if anyone wishes.
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AK

 

[Anti-K]

At this time I don't believe this is possible. From what I understand some say an "educated guess," is possible, but I don't believe they are talking about testing a mixed, partial profile sample which is what we've got in this case.

It's also important to consider that if they were able to say with any sort of certainty, what race this sample indicated--or doesn't indicate, ie, a person from Malaysia--that it would have been reported on...and I don't mean issued as a statement by LW.


*please note I am by no means an expert, but google is my friend

LE has claimed for years that they can determine race. Of course, all that they are really doing is making some determination based on ancestral background.
...

AK

 

[ScarlettScarpetta]

No...I think that was the OJ jury.

nope. It is right here.

WE have DNA that does not match a family member or anyone closely associated with the Ramseys. We have Touch DNA on her pants that matches the DNA in her panties.

In ANY OTHER CASE that is a smoking gun and points to an intruder.. Except here. Where the bias, hatred and profiteering has taken over and made this something it is not.

This case really is solved. We just don't know that person's name yet. IMO

 

[Tawny]

There have also been numerous cases mentioned in which DNA was irrelevant and didn't matter. This isn't some anomaly, it's not a glitch in the Matrix.

 

[ScarlettScarpetta]

There have also been numerous cases mentioned in which DNA was irrelevant and didn't matter. This isn't some anomaly, it's not a glitch in the Matrix.

There are no cases where the DNA does not matter. It either points to someone, excludes someone or has another source. But it is not irrelevant. ESPECIALLY when we don't know who it belongs to yet. It only can be put aside after the source is identified. In no case do they toss DNA before the case is solved.

 

[questfortrue]

There’s another interesting article which discusses the Adams case. The author of the article seems to have a predilection for the Beyesian argument over the Neyman-Pearson argument. To simplify without getting in over my head here (I’m sure AK will jump in, if I misstate my take on this ) both of these arguments deal with statistical probabilities in determining guilt.

http://www.math.nmsu.edu/~jlakey/m210/dawid-paper.pdf

In the case of Adams, both sides agreed to use the Beyesian calculations for determining probability of guilt. This actually favored the defense. The only link was the DNA in the case, Adams’ girlfriend said he was with her and the victim did not identify Adams and said the perp was in his early 20s. So, while no one sat in on the jury’s decision making, it was supposedly just the DNA which was the major contributing factor in the jury’s decision of guilt. (BTW, this DNA was directly from Adams matching the DNA from sperm retrieved from the victim; take the comparison to the R case DNA as you will.)

Here’s what I found interesting: To restate – supposedly there wasn’t any other evidence linking Adams to the crime, just the strong DNA link. The appeals were lost, and although both prosecution and defense had agreed to use the one argument (Beyesian) in the court room, the “Appeal Court roundly rejected the attempt to school the jury in the rational analysis of probabilistic evidence, saying that ‘it trespasses on an area peculiarly and exclusively within the province of the jury, and that to introduce Bayes theorem, or any similar method, into a criminal trial plunges the jury into inappropriate and unnecessary realms of theory and complexity.‘ The task of the jury was said to be to ‘evaluate evidence and reach a conclusion not by means of a formula, mathematical or otherwise, but by the joint application of their individual common sense and knowledge of the world to the evidence before them. ‘“

It sounded like this jury convicted primarily on the basis of DNA, and, maybe, what they thought of the accused’s indefinable demeanor. (Been told by a defense attorney, a jury isn’t supposed to make conclusions based on demeanor, yet they do.)

But, wait a minute, what to do about an RN and the experts’ opinions about the chronic vaginal injuries in the JBR case. Also, there’s other testimony heard at the GJ which hasn’t been leaked. Hmm. This may be why DA Garnett ‘un-exonerated’ the R’s, in spite of knowing about the DNA not matched to the Rs. moo

 

[bettybaby00]

There’s another interesting article which discusses the Adams case. The author of the article seems to have a predilection for the Beyesian argument over the Neyman-Pearson argument. To simplify without getting in over my head here (I’m sure AK will jump in, if I misstate my take on this ) both of these arguments deal with statistical probabilities in determining guilt.

http://www.math.nmsu.edu/~jlakey/m210/dawid-paper.pdf

In the case of Adams, both sides agreed to use the Beyesian calculations for determining probability of guilt. This actually favored the defense. The only link was the DNA in the case, Adams’ girlfriend said he was with her and the victim did not identify Adams and said the perp was in his early 20s. So, while no one sat in on the jury’s decision making, it was supposedly just the DNA which was the major contributing factor in the jury’s decision of guilt. (BTW, this DNA was directly from Adams matching the DNA from sperm retrieved from the victim; take the comparison to the R case DNA as you will.)

Here’s what I found interesting: To restate – supposedly there wasn’t any other evidence linking Adams to the crime, just the strong DNA link. The appeals were lost, and although both prosecution and defense had agreed to use the one argument (Beyesian) in the court room, the “Appeal Court roundly rejected the attempt to school the jury in the rational analysis of probabilistic evidence, saying that ‘it trespasses on an area peculiarly and exclusively within the province of the jury, and that to introduce Bayes theorem, or any similar method, into a criminal trial plunges the jury into inappropriate and unnecessary realms of theory and complexity.‘ The task of the jury was said to be to ‘evaluate evidence and reach a conclusion not by means of a formula, mathematical or otherwise, but by the joint application of their individual common sense and knowledge of the world to the evidence before them. ‘“

It sounded like this jury convicted primarily on the basis of DNA, and, maybe, what they thought of the accused’s indefinable demeanor. (Been told by a defense attorney, a jury isn’t supposed to make conclusions based on demeanor, yet they do.)

But, wait a minute, what to do about an RN and the experts’ opinions about the chronic vaginal injuries in the JBR case. Also, there’s other testimony heard at the GJ which hasn’t been leaked. Hmm. This may be why DA Garnett ‘un-exonerated’ the R’s, in spite of knowing about the DNA not matched to the Rs. moo

Yea, even through appeals, he was still found guilty, which was where the whole "in isolation" comment came from.

Listening to Dr Krane right now, "statistical weights of mixed DNA profiles."

Fascinating stuff.

 

[Aleph]

LE has claimed for years that they can determine race. Of course, all that they are really doing is making some determination based on ancestral background.
...

AK

Yes. So they could presumably rule out a Malaysian factory worker if, say, the DNA pointed to European ancestry.

 

[DeDee]

Per Request by Venom, the following response to a post re: DNA, # 270, written this evening on the thread: Boulder police chief exonerates Fleet and Priscilla White in death of JonBenet Ramsey by I Must Break You will also now be available on the DNA thread.

Originally Posted by ScarlettScarpetta View Post
It really is. Why? Because it matches the DNA found in her underwear. The TDNA is right where one would expect someone to touch to assault her. That it matches the DNA sample in her underwear changes the whole ball game.

There are many things about this case that can be argued and debated. DNA is a final answer. This DNA is used to target suspects and exclude. In this case it all excludes the R's.

Bolded mine. I haven't really followed along much with this case lately, but I can't help myself whenever I see someone say that DNA is used to exclude, that is completely false. I've mentioned this in many other threads (full disclosure I used to be LE for a short time before I found it boring and went back in the Army), and I know any police officer worth his salt will tell you the same (it's the very first thing they mention in the police academy and any college level criminal investigation course when forensics is covered)... DNA is only inclusionary and never exclusionary. There are crimes committed every day where absolutely no DNA is left, does that mean no one committed the crime, since everybody would then be excluded? NO. The presence of the DNA only means that if matched that person would also become a suspect. It does not exclude other suspects from being involved in a crime.

Any questions?

 

[Venom]

Why thank you Dedee.

 

[bettybaby00]

Per Request by Venom, the following response to a post re: DNA, # 270, written this evening on the thread: Boulder police chief exonerates Fleet and Priscilla White in death of JonBenet Ramsey by I Must Break You will also now be available on the DNA thread.







Any questions?

Great job :great:

Meant to post earlier this earlier for those interested.

http://youtu.be/wVHo1Pjf210

"Statistical weights of mixed DNA profiles"

 

[questfortrue]

Per Request by Venom, the following response to a post re: DNA, # 270, written this evening on the thread: Boulder police chief exonerates Fleet and Priscilla White in death of JonBenet Ramsey by I Must Break You will also now be available on the DNA thread.


Any questions?

Indeed, very good job, DeDee!

DA Garnett has tacitly said that the DNA did not exonerate the Rs. But this “exclusion” seems like a myth that has been promulgated by the media, LW and is still stated on the H law firm website. Here’s a question: Is it simply easier for Boulder officials to let people believe the Rs are exonerated via DNA, so the pressure is off, until or unless a ‘smoking gun’ happens? moo

 

[bettybaby00]

Indeed, very good job, DeDee!

DA Garnett has tacitly said that the DNA did not exonerate the Rs. But this “exclusion” seems like a myth that has been promulgated by the media, LW and is still stated on the H law firm website. Here’s a question: Is it simply easier for Boulder officials to let people believe the Rs are exonerated via DNA, so the pressure is off, until or unless a ‘smoking gun’ happens? moo

It's on their website???????????????????????????????????!!!!!!

:banghead::banghead::banghead::banghead::banghead:

 

[Charterhouse]

I know we have discussed tDNA to death.
Would someone please source for me the actual documents that show all the tDNA that was found on JBR. I am having trouble finding the sources.
TIA.

 

[bettybaby00]

I know we have discussed tDNA to death.
Would someone please source for me the actual documents that show all the tDNA that was found on JBR. I am having trouble finding the sources.
TIA.

This should be interesting.

There is only one "report" showing items where DNA was found and tested.

It's really just a summary, and it's only based on the "strongest sample". it gives no data about which loci were identified, or which alleles are represented.

Now the arguing begins. One set of people will believe there is DNA not related to the Rs, end of story, there was an intruder, and that's that. Oh and the DA "exonerated" the Rs on this evidence.

Others will argue that it's not so black & white. The report mentioned above has a HUGE IF qualilifier, which in and of itself is cause for another argument. The sample was mixed, again more arguing, and the report states, IF minor component is a mixture, Rs wouldn't be excluded.

The argument stems from the idea that this was a "partial (only 10 loci), mixed profile.

This offers an excellent review of how mixed samples are analyzed. Yes we know JRB was the main contributor, but we don't know with certainty whether not the other minor component was from more than one contributor. That is b/c

3.5.4.3. Due to the possibility that the minor contributor’s alleles may be shared by the major contributor (and thus masked), determination of a single genotype for a minor contributor may be possible at only some loci (while multiple allelic combinations, or allelic drop out, are possible at other loci).

The "thus masked" is the problem. When this happens a 3 person sample can present as a 2 person sample, and therefore the lab should only state "at least" 2 contributors," which of course is not an absolute. Added to this is the issue of working with only 10 loci, instead of 13, which although acceptable, provides less info. This is why I believe there is the IF qualifier on the report.

Anyway that's the long and short of it from the prospective that the DNA proves nothing, but I'm sure there will be loads of counter arguments.

Very good site here about analyzing a mixed sample.

http://www.fbi.gov/about-us/lab/biometric-analysis/codis/swgdam-interpretation-guidelines

Beginning at section 3.5

 

[ScarlettScarpetta]

The funniest part of this is that the FBI has a full sample in CODIS. Enough said.. Really.

They would not have anything there that had no evidentiary or real value.

 

[Charterhouse]

Scarlett could you please source that. I would like to see the report. I am having a hard time finding it.
TIA

 

[bettybaby00]

Scarlett could you please source that. I would like to see the report. I am having a hard time finding it.
TIA

It's in CODIS, meeting the minimum of 10 markers. Still doesn't make it the "enough said," sample it's being presented as.

 

[Anti-K]

There’s another interesting article which discusses the Adams case. The author of the article seems to have a predilection for the Beyesian argument over the Neyman-Pearson argument. To simplify without getting in over my head here (I’m sure AK will jump in, if I misstate my take on this ) both of these arguments deal with statistical probabilities in determining guilt.

http://www.math.nmsu.edu/~jlakey/m210/dawid-paper.pdf

In the case of Adams, both sides agreed to use the Beyesian calculations for determining probability of guilt. This actually favored the defense. The only link was the DNA in the case, Adams’ girlfriend said he was with her and the victim did not identify Adams and said the perp was in his early 20s. So, while no one sat in on the jury’s decision making, it was supposedly just the DNA which was the major contributing factor in the jury’s decision of guilt. (BTW, this DNA was directly from Adams matching the DNA from sperm retrieved from the victim; take the comparison to the R case DNA as you will.)

Here’s what I found interesting: To restate – supposedly there wasn’t any other evidence linking Adams to the crime, just the strong DNA link. The appeals were lost, and although both prosecution and defense had agreed to use the one argument (Beyesian) in the court room, the “Appeal Court roundly rejected the attempt to school the jury in the rational analysis of probabilistic evidence, saying that ‘it trespasses on an area peculiarly and exclusively within the province of the jury, and that to introduce Bayes theorem, or any similar method, into a criminal trial plunges the jury into inappropriate and unnecessary realms of theory and complexity.‘ The task of the jury was said to be to ‘evaluate evidence and reach a conclusion not by means of a formula, mathematical or otherwise, but by the joint application of their individual common sense and knowledge of the world to the evidence before them. ‘“

It sounded like this jury convicted primarily on the basis of DNA, and, maybe, what they thought of the accused’s indefinable demeanor. (Been told by a defense attorney, a jury isn’t supposed to make conclusions based on demeanor, yet they do.)

But, wait a minute, what to do about an RN and the experts’ opinions about the chronic vaginal injuries in the JBR case. Also, there’s other testimony heard at the GJ which hasn’t been leaked. Hmm. This may be why DA Garnett ‘un-exonerated’ the R’s, in spite of knowing about the DNA not matched to the Rs. moo

Adam’s DNA was taken because he was arrested for a sexual offence. I don’t know what the offence was, but I know that it was something “sexual.” As I remember it, the Bayesian formula used primarily consisted of the DNA, the likelihood of having an alibi and the likelihood of not being identified by the victim (I think that the latter two stats were pulled out of someone’s butt), and I wonder what impact adding the arrest for a sexual offence might have had on the result.

At any rate, using probability theory of any kind to determine guilt seems to me a misuse. Probability when properly applied can be a good indicator, but it is most certainly not the end-all, be-all Bayesians would like to believe (for example consider weather forecasting).
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AK