DNA evidence may be used to identify bombmakers

[Shane Costello]

Michigan State University (www.newscientist.com/news/news.jsp?id=ns99993426) (a place I know and have an affection for) have hit on way to identify bombmakers by taking DNA samples from fragments of the exploded device. The work was done in association with the Michigan State police laboratory. The success rate seems a bit low, but the technology might improve in the future.

This thread might belong in the Science forum, but I think it's on a topical issue.

[sadluxation]

The New Scientist report is a bit off.
It makes quite a few assumtions;
1)The bomb maker is going to touch parts of bombs long enough for a substantial amount of cells to be planted on the object.
2)They are not going to use gloves to handle explosives and/or bomb making equipment (Which is quite likely).
3)The completed device will not be in contact with other persons, guilty party, or innocent.

Unfortunately they got the DNA technique name wrong. It should be LCN (Low Copy Number), not STR, as all DNA profiling in the U.K. uses STR profiling with 10 STR's and 1 sex determinant gene.
This makes the probability of the profile 1 in a billion, as one STR has a 1 in 10 probability of being the same as any other individual.

LCN has proven unuseful in normal crime detection, but by using it in explosive detection, it can be used to pin-point to a single DNA profile.
Ideally, one of the creator.

[Shane Costello]

Originally posted by Sadluxation:
The New Scientist report is a bit off.
It makes quite a few assumtions;
1)The bomb maker is going to touch parts of bombs long enough for a substantial amount of cells to be planted on the object.
2)They are not going to use gloves to handle explosives and/or bomb making equipment (Which is quite likely).
3)The completed device will not be in contact with other persons, guilty party, or innocent.

The article states clearly that these conclusions were reached under controlled experimental conclusions, and that the sucess rate was rather low. One of the researchers themselves describes the technique as a "long shot". As for DNA from uninvolved persons coming into contact with the bomb, this is true of all situations that utilise genetic profiling. DNA evidence by itself wouldn't be conclusive enough to convict anyone.

Unfortunately they got the DNA technique name wrong. It should be LCN (Low Copy Number), not STR, as all DNA profiling in the U.K. uses STR profiling with 10 STR's and 1 sex determinant gene.
This makes the probability of the profile 1 in a billion, as one STR has a 1 in 10 probability of being the same as any other individual.

AFAIK all genetic profiling utilises differences in the patterns and numbers of STR between individuals, particularly microsatellite repeats. I've used this technique myself to distinguish cattle DNA. Individuals will have a unique number and pattern of short tandem repeats at specific loci of their genome.

[sadluxation]

Originally posted by Shane Costello



As for DNA from uninvolved persons coming into contact with the bomb, this is true of all situations that utilise genetic profiling. DNA evidence by itself wouldn't be conclusive enough to convict anyone.


Having worked in the National DNA Database, I know that not all DNA evidence would be in contact with other peoples DNA.
This is because we use Elimation samples and Criminal Justice samples to find if it relates to anyone either at the scene, or on the national database. That way, we can say if a police officer, or anyone living on the premises could have their DNA mixed with the samples collected.



AFAIK all genetic profiling utilises differences in the patterns and numbers of STR between individuals, particularly microsatellite repeats. I've used this technique myself to distinguish cattle DNA. Individuals will have a unique number and pattern of short tandem repeats at specific loci of their genome.


You don't get any more Brownie points for repeating what I've already said. I was more concerned with the technique the scientists were using.
Most profiling uses a standard called SGMplus. If you take repeats from different regions of the DNA, it causes immense problems when matching to a standard profile.

It seems that the Michigan scientistS used 13 STR's, which may, or may not correlate with other STR profiling.
This could make finding a bomb maker slightly more difficult, especially if you have to run their profile again in a different way than the standard.

Unfortunately the article did not give the required information.