It's a little bit more complicated than that....
There is a small but finite chance that two (unrelated) people will share a DNA profile, which is not quite the same as sharing DNA. As it currently stands, a DNA profile samples only a very small number of points in the genome. As such, the exact probability depends on the specific test used.
The current UK forensic standard test (SGM plus) only looks at 11 points in the genome. Even so, the chance of two people sharing a profile on this system is 1:1,000,000,000.
If you sequenced the entire genome to generate the profile, then the chance of two people sharing a DNA profile is, to all intents and purposes, 0.
The film didn't seem to give any details about how the genetic test was done
Interestingly, if you used a whole genome profile, you would almost certainly be able to distinguish between identical twins as well. It has been estimated that each pair of identical twins carry about 400 mutations that occur after separation, but early enough in development that they are detectable in the adult.
Lovely film, thanks for sharing.
(, Sun 14 Oct 2012, 10:23, Share, Reply)