Boy, oh boy. I really didnt want to get into the DNA stuff that deep. I should know when Im in over my head. Or as my dad always said, Its better to keep your mouth shut and let people wonder if youre stupid than to open it and confirm it for them. But here goes:
My understanding about the distal stain 007-2 is this (and if Im incorrect, somebody/anybody jump right in and correct me). One of the two blood stains that was found in the crotch of her panties was identified as Exhibit #7 when it was first processed. At that time it was determined that the major component (the blood itself) belonged to JonBenet. They recognize that this sample was mixed with a minor component belonging to
at least one other person. Their determination at that time was that if the minor component were from only one person, nine named individuals could not be the contributor. But they recognized that if there were
more than one contributor, those nine named individuals
could not be excluded.
(Here is where my ignorance may show through.) Later with advances in the technology, they were able to separate the minor component from the other blood stain for further testing and managed to enhance the results to raise the 9 markers and one faint marker to 10 full markers making the results meet the minimum requirement for entry into CODIS. As I understand all this, that minor component (since it was segregated from the sample identified as #7) was labeled as distal stain 007-2. The meaning of the word distal Im not certain of as to how it relates in DNA testing. Is it referring to where it was physically found within the blood stain (on the outer boundaries away from the center), or is it referring to where the elements of the DNA nucleotides are found in relation to the gene sequence (
http://en.wikiversity.org/wiki/Distal_promoter)?
Again, Im getting in way over my head here even attempting to speculate. But it was this segregated minor component that in earlier testing had had the if qualifier attached to it. I dont know whether the later testing was able to determine the exact number of contributors; but from what I understand so far, with so few markers (9-1/2) it seems like a stretch to attach too much significance to it -- especially considering the size of what was found (1/2 ng, or about 100 to 150 cells). Add to this the point from my previous reference to the Phantom of Heilbronn. Investigators had used sterile swabs for their DNA testing before discovering that sterile didnt necessarily mean free from human DNA. I see too many possibilities for human error in evidence handling (e.g., a lab technician using latex gloves as was acceptable practice in 1996, but handling multiple items of evidence thereby transferring microscopic trace amounts of DNA from one item to another) to think that the reliability of what has been thrown out there by Lacy is sacrosanct. As far as I can determine from looking for a source, she was the only one with access to the evidence who claimed that there was a match between the DNA in distal stain 007-2 to the tDNA found on the waistband of the leggings. But even using the word match in regards to DNA testing shows a lack of understanding of the process and the science behind it. At most one could say there is a high statistical probability that two samples are from the same person. But considering the fact that in this case, one was a partial DNA profile barely meeting the requirement for CODIS acceptance, and the other was too low to be accepted... Well, you can see the stretch it is to say the two are a match.
Cynic again discusses this very nicely in his first post in this thread at FFJ (there are also several other noteworthy posts in this thread by him and by
KoldKase as well):
DNA revisited in light of James Kolars book - Forums For Justice[Note that in Cynics Post #12, he mentions that The TDNA found on the leggings/long johns matched the waistband of the Bloomies. (All partial DNA profiles.) Could Lacy have confused which of the samples was the match that she referred to?]
