CA - Joey, Summer, Gianni, Joseph Jr McStay Murders - Feb 4th 2010 #15

[oceanblueeyes]

Thanks for clarifying Mony, and agree from what you say. I haven't been able to listen to the testimony yet, but did Perlin state what the nature/source of the DNA was from? It would be good to know IMO. There are only certain things they can obtain DNA from at a crime scene. Usually it is in the form of bodily secretions/fluid, skin cells, fingerprints, clothing, a weapon, etc.
So pity he didn't elaborate on that?

This is probably the stupidest question I've asked. Or maybe not. Lol!

Anyway here goes....Does anyone know if there have been any studies that have shown that traces of human DNA can be found in the soil itself even without a body or skeleton being present?

TIA!

 

[MrsPC]

This is probably the stupidest question I've asked. Or maybe not. Lol!

Anyway here goes....Does anyone know if there have been any studies that have shown that traces of human DNA can be found in the soil itself even without a body or skeleton being present?

TIA!

Yes, I posted about it last night - post #1017
CA - Joey, Summer, Gianni, Joseph Jr McStay Murders - Feb 4th 2010 #15

 

[oceanblueeyes]

Exactly. That is why there is a problem trying to use highly degraded DNA. It is taking the validity and certainty of DNA testing and taking it into speculative, potentially faulty territory.

Didnt he say the best way to still evaluate DNA is the way its being done now, and what is widely accepted in the forensic community?

The way they have analyzed this degraded DNA is it widely accepted, by peer reviews?

Imo

 

[missy1974]

As best as I can understand, CyberGenetics is CREATING the DNA profiles. IMO, they are extrapolating/amplifying the low grade DNA information they do have to create a profile. IMO, those extrapolations are subjective.

IMO, they are creating Frankenstein DNA.

Perlin did state the low grade DNA found is consistent with DNA that had been buried for three years. He felt that if it was DNA from a crime scene technician, the DNA would have been of much better quality.

All IMO.

I have listened to all of it, I may at some point go back to listen to piece it all together. I disagree that they are "CREATING" DNA. They are using statistical probabilities. And unlike manual interpretations (which is done in a lab) that are subjective, they are scientific and mathematical probabilities. The computer does it, not a person.

They take the electronic data and the computer figures out what the probable genotypes. If I understood correctly, it took the peak allele's in the electronic data and the computer can figure out the probable genotypes and allele pairs based on those peaks. IIRC from the earlier testimony from Beatriz, she said the computer runs the known samples through all the possible genotypes that the computer develops, something like 200 or 250 runs.

I do agree that Perlin stated the DNA that was found was degraded, it is not consistent with "fresh" DNA or DNA that was not exposed to the elements and degraded.

 

[Karinna]

This is probably the stupidest question I've asked. Or maybe not. Lol!

Anyway here goes....Does anyone know if there have been any studies that have shown that traces of human DNA can be found in the soil itself even without a body or skeleton being present?

TIA!

Not a stupid question at all ocean. An interesting question though.

 

[MrsPC]

Perlin kept touting how using TrueAllele is more accurate, etc. I would have asked him - if it's so accurate why does the FBI not use it. (In cross exam it was also noted in testimony that out of approx 350 DNA/Forensic labs across the country - only 10 use the TrueAllele software.)

 

[LadyL]

RSBM

I recall the unreliability of the timestamps on surveillance video systems came up in one case I followed.

"Millard's lawyer Ravin Pillay asked Plaxton about how digital video recorders are "prone to clock error over time." Most of the videos Plaxton was working with in the case had time-stamp errors, sometimes by three to four hours.

"When you encounter security camera video, you have to be very careful with attempting to fix a time that's out on the video, fair?" Pillay asked. Plaxton
responded yes."
https://www.cbc.ca/news/canada/hami...r-hours-after-tim-bosma-disappeared-1.3483358

I recall in his testimony he cited various methods that are used to test and correct the time, by sychronizing the video to known events. It was eye-opening. This was video created in 2013.

Since LE weren't given permission to remove the McStay neighbour's computer, they couldn't check and correct any potential time error. I was confused at first why the footage was entered into the record by the neighbour: I think it must be becauss it doesn't have the reliability of forensic evidence.

So, IMO, the puzzle about the time of the truck leaving might simply be a timestamp error.

[bbm]

thanks neighbour
they were only trying to find two toddlers & their parents ... nothing that important
thanks again

 

[oceanblueeyes]

Yes, I posted about it last night - post #1017
CA - Joey, Summer, Gianni, Joseph Jr McStay Murders - Feb 4th 2010 #15

I log off pretty early everyday so I must have missed it.

Thank you kindly for linking it again,MrsPC.

So these degraded DNA profiles may just be soil artifacts, and not even connected to the case or victims?

I'm glad my question wasnt all that stupid after all. Ha

Imo

 

[Karinna]

I think a good question maybe to have asked was if the expert stated he believed it was DNA that had survived for 3+ years in a grave out in the elements of the desert, what type of DNA could possibly have survived that long whereas other DNA didn't and was too degraded to yield a conclusive forensic result?

 

[mrjitty]

In Jennifer Mitchley's testimony at about 28:53 she stated that the timestamp on the video matched the time on her computer clock.

Thanks I missed this!

 

[MrsPC]

I think a good question maybe to have asked was if the expert stated he believed it was DNA that had survived for 3+ years in a grave out in the elements of the desert, what type of DNA could possibly have survived that long whereas other DNA didn't and was too degraded to yield a conclusive forensic result?

He actually was asked about that...and he claimed that the items were somehow "protected" from the enzymes of the decomposing bodies that would have broken down the DNA. And that makes no sense at all since the white cords and red tie-down were wrapped around Joseph. Joseph's body fluids/enzymes would certainly have "leeched" onto the cords IMHO.

 

[mrjitty]

And unlike manual interpretations (which is done in a lab) that are subjective, they are scientific and mathematical probabilities. The computer does it, not a person.

True, but the computer does it within the models / algos which humans created.

So in this case as I understand it, decision making went into extrapolating the profiles - then the computer runs its process

 

[MrsPC]

True, but the computer does it within the models / algos which humans created.

So in this case as I understand it, decision making went into extrapolating the profiles - then the computer runs its process

Exactly...the person using the TrueAllele software inputs certain parameters.

 

[Karinna]

He actually was asked about that...and he claimed that the items were somehow "protected" from the enzymes of the decomposing bodies that would have broken down the DNA. And that makes no sense at all since the white cords and red tie-down were wrapped around Joseph. Joseph's body fluids/enzymes would certainly have "leeched" onto the cords IMHO.

Agree, it doesn't make sense in my opinion either.

 

[oceanblueeyes]

Perlin kept touting how using TrueAllele is more accurate, etc. I would have asked him - if it's so accurate why does the FBI not use it. (In cross exam it was also noted in testimony that out of approx 350 DNA/Forensic labs across the country - only 10 use the TrueAllele software.)

Wow! Only 10 out of 350 is a unbelievably low number.

I'm glad to know the prosecution brought all of this to the attention of the jury.

I truly think in the end all of the degraded DNA testimony will be garbage in...garbage out. Imo it just isnt reliable enough to consider one way or the other, imo.

The jury will go by all of the other evidence which has been presented to make their decision.

The defense cant even prove the degraded DNA even belongs to someone else involved or is even connected.

Imo

 

[MsBetsy]

Wow! Only 10 out of 350 is a unbelievably low number.

I'm glad to know the prosecution brought all of this to the attention of the jury.

I truly think in the end all of the degraded DNA testimony will be garbage in...garbage out. Imo it just isnt reliable enough to consider one way or the other, imo.

The jury will go by all of the other evidence which has been presented to make their decision.

The defense cant even prove the degraded DNA even belongs to someone else involved or is even connected.

Imo

I agree. I think it will prove to be insignificant considering the circumstances. Imo

 

[missy1974]

Perlin kept touting how using TrueAllele is more accurate, etc. I would have asked him - if it's so accurate why does the FBI not use it. (In cross exam it was also noted in testimony that out of approx 350 DNA/Forensic labs across the country - only 10 use the TrueAllele software.)

Are you sure that the FBI doesn't use a probablistic genotyping software? TrueAllele is not the only software program out there. I don't know the answer to this question, but I do know that TrueAllele isn't the only software program developed to do the same thing, STRMix is another one that we have heard in the trial.

 

[missy1974]

Wow! Only 10 out of 350 is a unbelievably low number.
Imo

Again.... this is just for this specific software program. There are others, we don't know the numbers on those. I would be interested actually lol But just like other labs use different extraction programs like Identifiler, minfiler, yfiler, etc., we don't know the numbers on that and I think it's misleading in the sense that Perlin was only testifying about his own software, not competitive software that does the same thing. Just doing a quick search, I'm guessing his major competitor is STRMix... Home | STRMIX

 

[geevee]

Perlin kept touting how using TrueAllele is more accurate, etc. I would have asked him - if it's so accurate why does the FBI not use it. (In cross exam it was also noted in testimony that out of approx 350 DNA/Forensic labs across the country - only 10 use the TrueAllele software.)

During the cross, Daugherty asked Perlin about one of the highest loci peaks and said wasn't it true that in Bode's report they stated it was likely bacteria - Perlin said they rarely or never read reports.

I get that they're trying to take human subjectivity out of the equation but it seems at least seeing what the forwarding lab says about their results might be prudent and help to avoid some errors.

 

[missy1974]

During the cross, Daugherty asked Perlin about one of the highest loci peaks and said wasn't it true that in Bode's report they stated it was likely bacteria - Perlin said they rarely or never read reports.

I get that they're trying to take human subjectivity out of the equation but it seems at least seeing what the forwarding lab says about their results might be prudent and help to avoid some errors.

From what I understand, they look at the data... not someone's interpretation of the data, because that interpretation is subjective. They take the electronic data and the computer does it's thing. It takes the subjectivity out of the equation.
JMO