Hello & a Question about the DNA evidence

by DNAman 15.04.14 18:11

Hello, I just registered. I've been following this case for years & posted occasionally on forums & twitter. I may not have much time to post here, but I'll be reading with interest.

I have always been rather frustrated by the DNA evidence in this case & in particular Lowe's report. I have a good understanding of forensic DNA methods & I can't help but think that much more could be gleaned from the actual data FSS generated than what is in Lowe's report. I was wondering whether anyone has ever been able to get access to the actual data upon which Lowe's report is based? The actual genetic loci tested & the alleles found. The profiles of Madeleine, Kate, Gerry, Amelie & Sean would be of great use as well, but may be confidential.
If that information has not been obtained before does anyone know whether it would be possible to obtain it via a Freedom Of Information request?

OK that's two questions so I'd better stop there.

by worriedmum 15.04.14 20:53

I don't know the answer to this question, but I would like to ask one of you as you have expertise in this area.
Could you please put Gerry Mccann's quote from this interview, about DNA , into a scientific context for me..

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from 40 seconds onwards...

by DNAman 15.04.14 22:04

OK, he says the DNA is "mixed up" which makes no sense at all. He also says it was from 5people which could be true, but would be very unlikely. Lowe said 3 to 5 people, but what he did not say is that it was most probably only 3. I could explain why, but it would take a long time. Why three people? Well that is a big question. We must assume that if Madeleine's dead & decomposing body was in the car great efforts would have been made to clean it to remove the smell. This would leave only small traces of her DNA. DNA from someone else could easily contaminate the car boot. One or two skin cells would be enough.
It is possible that the DNA in the car boot came from other members of the McCann family, but it would have been trivial for FSS to have proved this either impossible, possible or likely. The fact that Lowe's report does not mention do this makes me wonder whether K,G,A&S were ruled out as potential donors due to the nature of the results obtained. If so it would then still be possible for the DNA to have come from three other people, less close relatives or people unrelated to McCann's. However the odds of three people not closely related to Madeleine producing the observed pattern of markers is quite small.
I cannot put any precise figures without seeing the raw data.
Does that help you at all?

by worriedmum 15.04.14 22:21

Thank you. I find the 'three or five''confusing-why not four?
Also , how does the number of permissible alleles differ?

by The Rooster 15.04.14 22:22

Nice one DNAman. Welcome!

by DNAman 15.04.14 22:41

worriedmum wrote:Thank you. I find the 'three or five''confusing-why not four?
Also , how does the number of permissible alleles differ?

It could be four. It is difficult to be certain how many people contribute to a sample. The number of contributors can be estimated by the number of alleles seen at an individual locus. If one or more loci show 5 alleles then it is possible that 5 people all homozygous for a different one of those alleles contributed to the sample. However it is rather unlikely that 5 people would all be homozygous at the same locus. It is more likely that three people, two heterozygous & one homozygous contributed the five alleles. Four people could contribute the five alleles if three were homozygous and one heterozygous at that locus. There are other possible combinations if the contributors share some of the same alleles. Of course allele frequencies in the population help to firm up which is most likely. That is ones reason why I would love to see the raw data. It would help to make sense, or not of Lowe's conclusions.

by **tigger** 16.04.14 8:06

Hello and welcome, roses

Having studied the basics of DNA some thirty years ago, enough of the facts were still in my memory to do a double take when Gerry said in the Swedish interview that of course there was Maddie's DNA in the car, because their DNA was there. ( not a litt. quote - I'll try to find it)

I like to call it the 'smartie version' of DNA.

I believe that Maddie was their daughter. i also believe she was never a healthy child. Which may be the reason the medical records were withheld.

The control sample was taken from a pillowcase. Why would the heel prick taken from babies not be more suitable?

As for Lowe's report, there are two versions as you know.
Clearly you know a lot about DNA and you explain it so clearly. But the excuse that the samples had been destroyed because they were compromised ( iirc by DNA of the technicians at the lab, which is ridiculous as their DNA is on record to prevent such accidents and we're also back to the 'smartie theory' of mixing DNA) is surely very strange? I thought that such evidence is retained in case new methods are developed which can give reliable results.

Considering that the Stephen Lawrence murderers were jailed on DNA evidence which I presume could not have been processed some ten years earlier and was kept safe during that time.

by raffa 16.04.14 9:21

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post by tony benett......... a very long but interesting read!!!!

by DNAman 16.04.14 9:31

tigger wrote:Hello and welcome,
Having studied the basics of DNA some thirty years ago, enough of the facts were still in my memory to do a double take when Gerry said in the Swedish interview that of course there was Maddie's DNA in the car, because their DNA was there. ( not a litt. quote - I'll try to find it)

I like to call it the 'smartie version' of DNA.

I believe that Maddie was their daughter. i also believe she was never a healthy child. Which may be the reason the medical records were withheld.

The control sample was taken from a pillowcase. Why would the heel prick taken from babies not be more suitable?

As for Lowe's report, there are two versions as you know.
Clearly you know a lot about DNA and you explain it so clearly. But the excuse that the samples had been destroyed because they were compromised ( iirc by DNA of the technicians at the lab, which is ridiculous as their DNA is on record to prevent such accidents and we're also back to the 'smartie theory' of mixing DNA) is surely very strange? I thought that such evidence is retained in case new methods are developed which can give reliable results.

Considering that the Stephen Lawrence murderers were jailed on DNA evidence which I presume could not have been processed some ten years earlier and was kept safe during that time.

Destruction of samples is completely unacceptable. If it has been done everyone including Kate and Gerry(if they are innocent) should be furious.

by **tigger** 16.04.14 9:58

Thank you ! roses

As you don't have much time I'm quite happy to search out information you'd like to read. So for a start I'll look for the report stating the samples were destroyed.

The 'contaminated' samples had previously been kept in high security locations according to the press.

I'm talking about primary information and not the interpretation and conclusions of others as it would imo good to avoid long tracts from other sites and blogs and keep it factual. winkwink

This is the link to the two Lowe reports on McCannfiles.com ( may have to scroll down a bit)
The destruction of samples mentioned there is not the document I'm looking for, there is a later one.

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by Guest 16.04.14 10:36

Occasionally I have to collect samples for analysis, the results of which may be used in legal proceedings. UK Police procedures are followed, in that the sample is split into three, one for the investigators, one for the party being investigated and lastly one for the courts, that could be analysed should there be any dispute between the opposing parties about the results.

Now I don't know anything about the procedures in Portugal, but forensics is not a new science so I would expect they would have a similar procedure, so there may well be other samples in existence despite the destruction of the ones at the FSS.

I guess that any defending party might be very reluctant to part with their sample and there may have to be some sort of legal proceedings for the investigators to get hold of the court's sample especially if there is no prosecution in sight. But didn't GA resently allude to further analyses being carried out?

by Guest 16.04.14 14:41

Hello DNAman,
do you think this will help you???

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hopefully!!!!

by XTC 16.04.14 23:32

HI DNAman and tigger

Is it my wrong interpretation or does the reading of the Lowe Report suggest that he is trying to make the parental profile fit
the 15 markers found from the 38 within in the sample?

Reading it I'm assuming that Lowe has a sample gleaned from the Scenic which has 38 components in it and out of the 38 he has
tested the 19 parental markers against all of the 38 components ( two parental contributors at least in the 19 markers) and that within the
remaining 19 ( 38 total components in all - minus the known 19 parental markers) there could be between 1 or 3 other contributors
within the remaining 19?

What's making my head scratch a bit is if he had of said that out of the 38 components 19 match Madeleine's parental profile - this matches
half the components within the sample total of 38 and therefore of the 19/38 - 15 of the parental profile matches from the overall 19
of Madeleine's pillowcase profile. Then the other 19 don't match the parental/Madeleine's 19 markers thereby excluding them. Yet again
I'm assuming - and may be way out but where does " mixed " come into play?

Did he test the heel stick profile against all 38 components for exclusion? Bigger the profile better the interpretation - is that true?
The only test against the pillowcase was JRB/1 ( blood in a cardboard frame) confirming that the pillowcase came from a child of theirs.
Yet would the later sent heel stick profile not be a better provenanced test against the questioned sample? The results of that are known so
just for accuracy why not test the result from that against the full DNA profile of Madeleine?

p.s. I take it all the results of all the testing will still be around somewhere but will only be re-visted if the investigation requires it.
I'm uncertain that the tests will ever see the light of day again though but live in hope.

I look forward to some answers and advice.

by DNAman 17.04.14 0:07

I'm sorry XTC, you seem to be very confused about what Lowe says & what the DNA markers actually are. I'll try to give you a detailed answer over the weekend. Don't have time right now.

by DNAman 17.04.14 0:12

Helene1 wrote:Hello DNAman,
do you think this will help you???

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hopefully!!!!

Thanks, I had seen this before, but had forgotten it was in the files. What I really need is a similar lab report for the Renault scenic boot sample. K,G,A&S profiles would also help a great deal. I may post something just based on Maddie's profile & alleles frequencies, but it won't amount to anything earth shattering I'm sorry to say.

by Okeydokey 17.04.14 0:26

I believe there was deliberate misdirection at the time.

For instance it was said that there was something like a 1 in 200 match chance on the hire car DNA and that would mean that there could be two or three people from the forensic unit who could match for the DNA.

But that is irrelevant. This was a (fairly new) hire car and therefore the question is who out of the people who had used the car. It was nonsensical to make the point of comparison the general population. In fact the people who had used the car would in principle have been known.

by DNAman 17.04.14 9:50

Okeydokey wrote:I believe there was deliberate misdirection at the time.

For instance it was said that there was something like a 1 in 200 match chance on the hire car DNA and that would mean that there could be two or three people from the forensic unit who could match for the DNA.

But that is irrelevant. This was a (fairly new) hire car and therefore the question is who out of the people who had used the car. It was nonsensical to make the point of comparison the general population. In fact the people who had used the car would in principle have been known.

Quite correct, although I think the match chance might be a bit lower. Why were the people who had hired the car not traced & DNA profiled? Why were other members of the McCann family & friends not traced & DNA profiled? Whilst this would not have proved that Maddie did not contribute to the car sample it could have proved that the sample profile could have been generated by three people who did use the car. Actually this might have been a failure on the part of the PJ & Amaral. They were leading the investigation and could have requested further tests. However Lowe's report seemed to rule out the possibility that further tests would shed more light. If the McCanns had already indicated their intention to leave Portugal PJ might have felt they had little time to act.

by Tombraider 17.04.14 10:34

This comes from Lowe’s report where he states: - "DNA analysis uses a technique in which specific regions [areas] are seen and copied (or amplified) many times. A DNA profile obtained from biological material, such as blood, semen, saliva or hair may be compared with a DNA profile obtained from a reference sample of any person. In the case that the DNA profile of the particular person is different from the DNA profile of the biological material, then that person is not the source of that material. If the profiles are equal [match], then that person, together with other persons having the same DNA profile, may be considered as a potential source of the material."

So why wasn’t Madeleine considered a potential source ?

It is my understanding that in order for anyone to state that they identified a person or a person’s DNA from a sample there has to be enough components or markers that match the sequence of markers in that same persons reference sample. In relation to the sample found in the apartment Lowe states – “However, all of the confirmed DNA components within this result match the corresponding components in the DNA profile of Madeline McCann. “ - So they identified a person - (MM), therefore there had to be enough markers that matched the sequence of markers in her reference sample. It may not have been a full 100% match, but there was enough markers to identify her. If it was 15 / 19 markers and they all matched the sequence in her reference sample then there’s little doubt considering I believe they only need 13 in the USA and 10 in the UK for a positive ID.

The same principals should apply to the sample found in the vehicle.

by DNAman 17.04.14 11:13

Madeleine is considered to be a potential source. The problem arises because more than one persons (probably 3 people) DNA was present in the sample. So it is possible that these 3 (or less likely 4 or 5 ) people provided all the markers present in the sample including the 15 shared with Maddie.

Now the question becomes how likely is that? I am in the process of trying to make a rough calculation. With the full lab results I could make a more accurate calculation. However it is safe to say that it is highly unlikely (in the order of several thousands to one) that 3 people unrelated to Maddie could have produced such a DNA profile. However if one, two or three of the contributors was related to Maddie it becomes far more likely.

Now here is the crux of the matter. The 22 markers (37total minus 15Maddie) can help to establish whether K,G,A&S McCann were contributors to the 37 total markers. It should be quite easy to say YES they were potential contributors & most importantly it should be possible to say NO they probably DID NOT (odds of at least hundreds to one) contribute to the sample. Which of these is true is a matter of FACT based on which alleles make up the 37 total.

All that is needed to make the correct one of these statements is the profile obtained from the car boot sample and the DNA profiles of K,G,A&S McCann. These are things that the FSS had so it comes as quite a surprise that no such comment was made.

Profiles of McCann wider family & friends would allow further comment on the source of the DNA in the sample. Profiles of other users of the hire car might also be obtained and provide useful information.

by Tombraider 17.04.14 11:33

There will always be matching components because a child's DNA strand contains the genetic coding of the parents, this isn't unique to the this or any other DNA sample. If you are talking about chance in relation to other “random” genetic profiles corresponding/ matching., - siblings will only have a roughly 1 in 250,000 chance of matching over 10 markers, how then is it possible that at least 3 totally random, unrelated people as suggested, are supposed to be responsible for making up the genetic profile found in the sample in the hire car considering there will always be components /markers that are shared by others in the general population which they should have calculated for. These tests weren't or shouldn't have been done with the intention of profiling evidence of genetic relationship based on respective DNA profiles showing predictable biological inheritance patterns which identify relatedness ( common markers ) between parents / siblings / close family. The report by Lowe indicates that scientists could also have contributed, thats also nonsense and he should never have stated that either as the FSS used a data base containing their profiles solely for the purpose of eliminating them as possibly contributors. Because LCN testing is known to throw up extra markers there is also methods developed designed specifically to calculate for extra and eliminate markers that show up by chance.

by DNAman 17.04.14 12:15

Tombraider wrote:There will always be matching components because a child's DNA strand contains the genetic coding of the parents, this isn't unique to the this or any other DNA sample. If you are talking about chance in relation to other “random” genetic profiles corresponding/ matching., - siblings will only have a roughly 1 in 250,000 chance of matching over 10 markers, how then is it possible that at least 3 totally random, unrelated people as suggested, are supposed to be responsible for making up the genetic profile found in the sample in the hire car considering there will always be components /markers that are shared by others in the general population which they should have calculated for. These tests weren't or shouldn't have been done with the intention of profiling evidence of genetic relationship based on respective DNA profiles showing predictable biological inheritance patterns which identify relatedness ( common markers ) between parents / siblings / close family. The report by Lowe indicates that scientists could also have contributed, thats also nonsense and he should never have stated that either as the FSS used a data base containing their profiles solely for the purpose of eliminating them as possibly contributors. Because LCN testing is known to throw up extra markers there is also methods developed designed specifically to calculate for extra and eliminate markers that show up by chance.

We need to be careful not to create confusion over what is meant by marker. In the Lowe report a 'marker' is the same as an allele. 10 loci were tested (the norm for UK testing) these would give a maximum of 20 alleles or markers. In Maddie's case only 19 alleles are present in her profile because she is homozygous at one locus so this locus produces only one allele (marker) rather than two.

Otherwise what you say is largely correct. I will be making a longer post with all my thoughts regarding the DNA forensics soon. I dare say this has been done many times before, but I would like to re open the discussion. Perhaps on a new thread perhaps a blog to which I can link. I won't post again until I have all my thoughts,estimates & calculations assembled into one document.

by Tombraider 17.04.14 16:10

It’s now well known that extra markers are extremely common in LCN testing. What I believe isn’t common in forensic profiling is using those extra markers in an attempt to try and eliminate someone, which is what appears to have happened. How that sample got there, by chance or not, doesn’t alter the fact that the evidence sample according to the writer was ‘ genuine’ and that the genetic profile corresponded with the person who they were trying to locate. And I believe that is the reason that J. Lowe was unable to state with any certainty that in his ' opinion' the analysis eliminated her or ruled her out and also why he has not in his report stated the tests were inconclusive, only that in his opinion they couldn't determine whether or not she contributed to the sample.

by noddy100 17.04.14 17:09

Can I ask a more basic question please?
If Madeleine was in the apartment for several days in bed etc
what sort of cleaning could they have done to erase all traces of her?
Is it that easy?
Considering the blood and cadaver odour can be detected by dogs years later then surely there must have been
some of hers on clothes bedding cups etc even if it had been washed

by canada12 17.04.14 18:39

noddy100 wrote:Can I ask a more basic question please?
If Madeleine was in the apartment for several days in bed etc
what sort of cleaning could they have done to erase all traces of her?
Is it that easy?
Considering the blood and cadaver odour can be detected by dogs years later then surely there must have been
some of hers on clothes bedding cups etc even if it had been washed

Did Kate wash Madeleine's hats too? Surely there would have been sweat, etc., present in the hats? Even if Amelie had worn them - there should be two distinct DNA profiles. No?

by Tombraider 17.04.14 18:44

noddy100 wrote:Can I ask a more basic question please?
If Madeleine was in the apartment for several days in bed etc
what sort of cleaning could they have done to erase all traces of her?
Is it that easy?
Considering the blood and cadaver odour can be detected by dogs years later then surely there must have been
some of hers on clothes bedding cups etc even if it had been washed

This is a very good question noddy100., I would have thought it wasn't easy or even possible. It's a mystery why a sample of her DNA which could have been be used to create a control / reference sample wasn't located, though I believe attempts may have been made to identify one. It should have been seen as a priority as per procedures in vulnerable missing persons cases. Certainly there were attempts to identify hair samples without success but that most likely was down to the fact that they didn't have samples of the twins hair for comparison purposes.