Clarification required on DNA findings

Discussion in 'JonBenet Ramsey' started by MaskedAvenger, Jan 2, 2014.

  1. MaskedAvenger

    MaskedAvenger New Member

    Messages:
    10
    Likes Received:
    0
    Trophy Points:
    0
    Hi all, please forgive me if these questions have already been asked but I am looking for clarification regarding the DNA results in this case, specifically:

    What type of testing was used for the fingernails and underwear?

    How many markers were said to make up the major and minor components in each sample?

    If anyone could help me out on this, it would be greatly appreciated.

    Thank you :)
     
  2. Loading...


  3. DeeDee249

    DeeDee249 New Member

    Messages:
    8,022
    Likes Received:
    23
    Trophy Points:
    0
    Can't help you on the DNA (there are experts here who can) but as far as the fingernail DNA- none was found that was usable. It was degraded which meant it was not fresh, not from that night. Despite media reports, there was no match between what was under her nails and any other DNA. The coroner ADMITTED he used dirty clippers to cut her nails, clippers he had previously used on other dead bodies, without sterilizing them before using them on JB. He also admitted using the SAME dirty clippers on every finger when proper procedure required a different clean pair for each finger. Whether any usable DNA was obtained from her nails was a non-issue after that, as the contaminated evidence would never have been admissible.
     
  4. Mama2JML

    Mama2JML New Member

    Messages:
    1,233
    Likes Received:
    0
    Trophy Points:
    0
    Are you referring to the 1997 DNA results? (PM + DQAlpha & D1S80)

    The major component in each sample was matched to the profile of JonBenet. The minor component in the underwear revealed 4 foreign markers, the left hand fingernail clippings revealed 2 foreign markers & the right hand, 1 foreign marker.

    [​IMG]
    [​IMG]
     
  5. MaskedAvenger

    MaskedAvenger New Member

    Messages:
    10
    Likes Received:
    0
    Trophy Points:
    0
    Thank you for this information. So in a nutshell, the DNA collected from the fingernails could have been anyones, and has not been matched to any other item (contrary to what has been reported).

    Yes that is the test I was enquiring about, thank you. Four markers found on underwear. Not a huge amount and certainly not a full profile by any means.

    That said, and if I understand the protocol of mixed samples correctly, there only needs to be one distinct difference in any marker for a lab to exclude a person as a possible donor of the minor component found. In this respect, if the lab was able to clear everyone, then reporting this fact would be a fairly straight forward affair. What I don't get is the IF this THEN that part of the conclusion. To me, it sounds as if they compiled all the markers obtained from each item together, and used that as a control sample (profile) in which to test everyone else against......:doh:
     
  6. Venom

    Venom New Member

    Messages:
    1,304
    Likes Received:
    4
    Trophy Points:
    0
    Welcome. This thread [ame="http://www.websleuths.com/forums/showthread.php?t=199130"]A DNA expert will be available to answer your questions! - Websleuths Crime Sleuthing Community[/ame] has a lot of info on the dna.
     
  7. Mama2JML

    Mama2JML New Member

    Messages:
    1,233
    Likes Received:
    0
    Trophy Points:
    0
    An excerpt from Chapter 11 (DNA in the courtroom) from Dr. Dan Krane's Psychological and Scientific Evidence in Criminal Trials, discusses the testing method used in the JBR case circa 1997:

    "In 1993, PE introduced an improved kit that typed DQ-alpha and five additional genes, thereby improving the specifcity of this method. With this new kit, known as the Polymarker/DQ-alpha test, individual profile frequencies were on the order of one in tens of thousands, however it still was not as discriminating as RFLP analysis.

    The PE kits were widely used by forensic laboratories in the mid 1990s, but were gradually supplanted by STR tests beginning in about 1998. Commercial test kits for DQ-alpha and Polymarker testing have not been produced since 2002. However, a few labs still maintain stocks of the test strips to allow new samples to be compared to the results of these older tests. Because STR tests examine different loci using a different method, one cannot make comparisons among samples across methods."

    (Thompson & Krane, 2003)

    Read more here: http://www.bioforensics.com/articles/Chapter11.pdf
     
  8. KoldKase

    KoldKase New Member

    Messages:
    996
    Likes Received:
    6
    Trophy Points:
    0
    Here's a pretty good thread at FFJ on which poster and case researcher Cynic has gathered a lot of the information you are asking about:

    [ame="http://www.forumsforjustice.org/forums/showthread.php?t=10137"]DNA revisited in light of James Kolar’s book - Forums For Justice[/ame]

    There is some interesting discussion there, as well, which clarifies, or at least addresses, some of the questions about the DNA for which we still do not have answers, as the DNA reports have never been released...well, not to the general public, anyway.
     
  9. MaskedAvenger

    MaskedAvenger New Member

    Messages:
    10
    Likes Received:
    0
    Trophy Points:
    0
    Thanks for the links everyone :)

    Will follow them up and see how I go.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice