Amanda Knox guilty - all because of a cartwheel

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Kekule has published in Nature

which is one of the two most prestigious biological journals in the world. I found the link at PMF. The discussion there suffers from groupthink. Someone actually said that Wendy Murphy's article was better than Professor Kekule's. Ms. Murphy's article suffered from a number of factual errors. On the other hand, Professor Kekule's views are broadly similar to Drs. Johnson and Hampikian.
 
halides1 said:
To all,

Here is a link to an article in German by Alexander Kekule. He is an MD/PhD, and his work concerns DNA and viruses. As others have done, he points to the lack of blood as a deficiency in the evidence concerning the kitchen knife.

http://www.tagesspiegel.de/meinung/kommentare/Amanda-Knox-DNA-Spur;art141,2970520

Chris
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We have some unfinished business first: http://www.internationalskeptics.com/forums/showpost.php?p=5480609&postcount=1782

You used to be pursuing this tack with undisguised tenacity. I want you to explain how the Perugia crime lab relates to the Houston crime lab before we continue.

Alternately, we may agree that you've dropped the comparisons and we can go on to fresh business.
 
please explain the presence of many individuals' DNA on the clasp

stilicho said:
We have some unfinished business first: http://www.internationalskeptics.com/forums/showpost.php?p=5480609&postcount=1782

You used to be pursuing this tack with undisguised tenacity. I want you to explain how the Perugia crime lab relates to the Houston crime lab before we continue.

Alternately, we may agree that you've dropped the comparisons and we can go on to fresh business.
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Stilicho,

I made one and only one point with respect to the Houston lab. Personnel in this lab testified to something that was not true. You have misconstrued what I said; only you know whether it was done honestly or not.

While we are on the subject of unfinished business, neither you nor anyone else has answered my repeated question of how several individuals (not just Kercher and Sollecito) deposited their DNA on the clasp. Please explain how the DNA got there, and then we can go on to fresh business.

Chris
 
Jungle Jim said:
These are the principal factors in my decision:
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Thanks for being forward with your reasonings. It gives us something to work on to try and reach a common understanding. I'll work though these issues one at a time so we can go into depth on each one instead of just skimming the surface.


1. DNA of the victim is found on a knife in RS’s apartment.
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Properly stated, A DNA profile matching the victim was found when the knife was processed. This part I have no dispute with. But how was the DNA sample extracted from the knife? We've seen a picture presumably of the knife and where this DNA was supposed to have been and there is no visible flaw or scratch. There is also a video of a lab technician removing the DNA material with a solvent soaked piece of cloth held by a pair of metal tweezers. This same lab has tested many articles soaked with Meredith's blood and the process of testing, the DNA is extracted and amplified through PCR. Unless extreme measures are taken, this DNA is going to contaminate everything in the lab. For instance, that pair of tweezers probably has Meredith's DNA on them and it will be transfered to the solvent soaked cloth.

In order to conclude that the DNA came from the knife, it is necessary to exclude the probable alternatives. The alternative of the DNA coming from elsewhere in the lab is properly excluded by running a control test using the same equipment and the same procedure but using a different test object that is not expected to have any DNA. If DNA shows up on the control, you know that your test was probably contaminated. Furthermore, when a lab routinely runs control tests they can develop a statistical model for the level of contamination expected in the lab after processing evidence.

Quite simply, the lab in Italy did not run controls so their results have no scientific basis for accuracy.

There is also the issue of the provenance of this knife and how it came to being selected but I'll leave that for another time.
 
Dan O. said:
Thanks for being forward with your reasonings. It gives us something to work on to try and reach a common understanding. I'll work though these issues one at a time so we can go into depth on each one instead of just skimming the surface.




Properly stated, A DNA profile matching the victim was found when the knife was processed. This part I have no dispute with. But how was the DNA sample extracted from the knife? We've seen a picture presumably of the knife and where this DNA was supposed to have been and there is no visible flaw or scratch. There is also a video of a lab technician removing the DNA material with a solvent soaked piece of cloth held by a pair of metal tweezers. This same lab has tested many articles soaked with Meredith's blood and the process of testing, the DNA is extracted and amplified through PCR. Unless extreme measures are taken, this DNA is going to contaminate everything in the lab. For instance, that pair of tweezers probably has Meredith's DNA on them and it will be transfered to the solvent soaked cloth.

In order to conclude that the DNA came from the knife, it is necessary to exclude the probable alternatives. The alternative of the DNA coming from elsewhere in the lab is properly excluded by running a control test using the same equipment and the same procedure but using a different test object that is not expected to have any DNA. If DNA shows up on the control, you know that your test was probably contaminated. Furthermore, when a lab routinely runs control tests they can develop a statistical model for the level of contamination expected in the lab after processing evidence.

Quite simply, the lab in Italy did not run controls so their results have no scientific basis for accuracy.

There is also the issue of the provenance of this knife and how it came to being selected but I'll leave that for another time.
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Do you have a cite for this claim?
 
BobTheDonkey said:
All I get is a link back to your post??

Not exactly good form, old boy.

Do you have evidence (a.k.a. a cite) of your claim regarding the lack of a control?
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The prosecution is the one making the claim that their test is valid. I cannot prove that they didn't have controls. I can only state that there has not been evidence of such controls presented. My claim can be easily falsified by showing that there were controls.

To help you get started, Here is a document that details what is expected of a lab in the US before they can produce forensically valid results: http://www.fbi.gov/hq/lab/fsc/backissu/july2004/standards/2004_03_standards02.htm
This of course does not apply to Italian Labs but they should have similar procedures. Someone should be able to find the equivalent Italian document and the accreditation for the lab in question. Without these documents, the DNA tests performed by the lab have no meaning.
 
Dan O. said:
The prosecution is the one making the claim that their test is valid. I cannot prove that they didn't have controls. I can only state that there has not been evidence of such controls presented. My claim can be easily falsified by showing that there were controls.

To help you get started, Here is a document that details what is expected of a lab in the US before they can produce forensically valid results: http://www.fbi.gov/hq/lab/fsc/backissu/july2004/standards/2004_03_standards02.htm
This of course does not apply to Italian Labs but they should have similar procedures. Someone should be able to find the equivalent Italian document and the accreditation for the lab in question. Without these documents, the DNA tests performed by the lab have no meaning.
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Whaaaaaaaaaat? You are making a wild claim that no controls were used, and then when asked where you got this info you reply that it's up to me to prove you wrong?

How about you try again. Where/what makes you think that no controls were used?
 
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If the DNA results were that easily invalidated, one would think that the AK/RS defense would have had a field day with that issue, unless one assumes that the defense was incredibly incompetent.
 
On the one hand Dr Stefanoni testified that there were controls: the tests were witnessed by the expert hired by the Kerchers: the protocols in place were confirmed by Biondi. On the other hand Dan_O says they were all lying or mistaken. You pays your money .....
 
halides1 said:
To all,

Here is a cite for the lack of controls with respect to the knife:
http://www.sciencespheres.com/2009/10/lcn-dna-profiling-part-ii-watch-where.html
http://www.sciencespheres.com/2009/10/methods-of-polizia-pseudoscientificaa.html

A good negative control would have been to test other kitchen knives for Kercher’s DNA. Since no other knives were taken into custody, these controls could not have been done.

Chris
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I've skimmed the links, apologies if I've missed where this is answered, but is there a reason why using a knife as a control would be important? Presumably the speculation isn't that there might be something special about knives in general, or Kerchers DNA, that would make it more likely that her DNA would falsely be detected on the knife? The question is surely whether the replication process could be amplifying noise/contamination.

If one was doing this kind of test hoping to find genetic material in a rape case, would it be normal practice to use a control vagina?
 
halides1 said:
To all,

Here is a cite for the lack of controls with respect to the knife:
http://www.sciencespheres.com/2009/10/lcn-dna-profiling-part-ii-watch-where.html
http://www.sciencespheres.com/2009/10/methods-of-polizia-pseudoscientificaa.html

A good negative control would have been to test other kitchen knives for Kercher’s DNA. Since no other knives were taken into custody, these controls could not have been done.

Chris
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Just curious.

You've shared a number of comments about what could have gone wrong, or what could been done differently, or how someone somewhere else screwed up.

In your personal, professional opinion, having reviewed what you have, what do you think the odds are that in this particular case the DNA on that knife was not Kercher's?

As a follow-up question why do you think that, on the basis of little more than a rumor that such DNA had been found, Sollecito immediately assumed it was true and attempted to fabricate an explanation for its presence?
 
Of course, any putative deficiencies in the DNA test are irrelevant, since the owner of the knife as said that DNA would be expected in it, because he would have pricked the victim's hand with it, during a fantasized dinner party.

Bummer, I know, but even if no DNA had been found on the knife, it wouldn't matter. The accused identified the murder weapon (since his story was established as false).
 
control experiments are the hallmark of good science

shuttlt said:
I've skimmed the links, apologies if I've missed where this is answered, but is there a reason why using a knife as a control would be important? Presumably the speculation isn't that there might be something special about knives in general, or Kerchers DNA, that would make it more likely that her DNA would falsely be detected on the knife? The question is surely whether the replication process could be amplifying noise/contamination.

If one was doing this kind of test hoping to find genetic material in a rape case, would it be normal practice to use a control vagina?
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shuttit,

From the second of the two links I provided,

The kitchen knife was retrieved from Raffaele's kitchen drawer some 5 days after the murder. It was reportedly taken to the police station, sat on a detective's desk for a day or so, and then was mailed to the lab in an ordinary box. Hardly the kind of careful handling you would expect of evidence slated for conventional DNA testing, let alone the hypersensitive LCN profiling. The blade DNA profiling was performed by an improvised, non-reproducible, never-validated method with deficiencies described in detail in LCN DNA Parts I and II. In fact we can add extremely poor evidence handling to the list of 9 deficiencies compiled in Part II to make it 10 testing deficiencies.


The low copy number test on the kitchen knife was apparently performed without any negative controls. In negative control tests you perform the DNA multiplication and profiling, without adding any sample to the system. Often when this is done, as if by magic, a DNA profile emerges. It has come from a minute amount of contamination from the equipment, or the laboratory. These negative controls are essential to performance of LCN work, as shown in Part II of this series. They were either not performed, or not reported by Stefanoni.

Perhaps even more important for the knife DNA, no control experiments were run to follow the handling of the item from the field through to the laboratory. That is, to see if other, random objects retrieved from the same drawer and handled in the same, unprofessional way, might also appear to have DNA on them. It would be interesting to hear the prosecution spinning a sinister implication out of DNA found on a can opener. Perhaps one can use canned peas for satanic rituals. Would Meredith's DNA be found on a spoon from the same drawer? How about Filomena's? Would the spoon then be cast as the murder weapon, whether it matches any wounds or not?


All this is preposterous of course. But think about it. We have no way of knowing what the supposed knife DNA means, or where it came from, because no comparison tests of any kind were performed.

[Endquote]

One can find plenty of other information about LCN at this site, also.

Chris
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story about the knife

Megalodon said:
Of course, any putative deficiencies in the DNA test are irrelevant, since the owner of the knife as said that DNA would be expected in it, because he would have pricked the victim's hand with it, during a fantasized dinner party.

Bummer, I know, but even if no DNA had been found on the knife, it wouldn't matter. The accused identified the murder weapon (since his story was established as false).
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Megalodon,

Far upthread I posted several times on this erroneous argument. PM me if you cannot find them.

Chris
 
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