Nearly thirty years after a six-year-old was murdered in her own home on the night after Christmas, a Utah private investigator has done something extraordinary — he mailed a public appeal directly to
According to Jason Jensen if you go to his Facebook a lot of DNA from the crime scene is unreliable as not all DNA is the same in terms of how it is acquired.
The reason the DNA evidence in this case is sketchy is bc the Boulder police did a sloppy job in their initial sweep of the crime scene. As a result, much of the DNA there is was damaged or contaminated.
As to how they can rule out the parents, this has to do w the way that you use DNA evidence to “match” it to the criminal.
Basically, all of DNA matching is a ruling out process. While no two individuals have the same DNA, the evidence might only give you a small sequence of it to look at. So when evaluating DNA, you take the sequence and then just run a simple numbers game:
How many people have this sequence? For a good sample, it’s usually around 1 in 150,000 or so. (Good defense attorneys will take advantage of this. They’ll say that in a city of 2.5M people, that this means 80 different people could be the killer. But good prosecutors know this too, and can close this loop.) Here’s the take home though, even if the strand you have isn’t great, you can still compare it to the DNA of the parents and say, definitively, that they don’t have such a sequence in their DNA. And that’s how you rule them out.
Poor baby. I hope you rest in peace.
Don’t they automatically take DNA samples from incarcerated people now? Can they match this Gary person to this?
According to Jason Jensen if you go to his Facebook a lot of DNA from the crime scene is unreliable as not all DNA is the same in terms of how it is acquired.
Thank you
If the DNA evidence is sketchy, then why would they rule out the parents?
The reason the DNA evidence in this case is sketchy is bc the Boulder police did a sloppy job in their initial sweep of the crime scene. As a result, much of the DNA there is was damaged or contaminated.
As to how they can rule out the parents, this has to do w the way that you use DNA evidence to “match” it to the criminal.
Basically, all of DNA matching is a ruling out process. While no two individuals have the same DNA, the evidence might only give you a small sequence of it to look at. So when evaluating DNA, you take the sequence and then just run a simple numbers game:
How many people have this sequence? For a good sample, it’s usually around 1 in 150,000 or so. (Good defense attorneys will take advantage of this. They’ll say that in a city of 2.5M people, that this means 80 different people could be the killer. But good prosecutors know this too, and can close this loop.) Here’s the take home though, even if the strand you have isn’t great, you can still compare it to the DNA of the parents and say, definitively, that they don’t have such a sequence in their DNA. And that’s how you rule them out.