Evolutionary CSI to the rescue!

Six medical workers in Lybia have been convicted of deliberately injecting 426 children with HIV-infected blood. The defendants have all been sentenced to death, although court appeals are still likely to take place.

As it should be expected, the public, as well as the families of the victims are outraged at the situation.

Although the courts have found the defendants guilty, the really interesting thing is that scientists investigating the evolutionary history of the virus have recently concluded that many independent sets of evidence point to the innocence of the medical workers.

How could this be done? Imagine yourself trying to investigate what really happened. One of the very first things you would have to do is create hypotheses that might explain the current situation. One model could work on the assumption that the evolutionary history of the current strains of HIV was somehow caused by the accused workers. This presupposes that they were employed at the hospital prior to the outbreak. Under this model, we are also presupposing their guilt (although it would still be possible the strain was introduced into this child population through sources other than the medical workers).

But what if we presuppose that they are absolutely innocent? How could that be explained beyond any reasonable doubt? Well, we'd still have to create an account of the evolutionary history of the HIV strains, but if the different strains started to separate from one another prior to the time when these medical workers were hired, then the defendants could not have possibly have been responsible, since they were not at the hospital. These are the two scenarios, in graphic form:

Model 2 is exactly what the scientific evidence points to. The original infection took place years before these six innocent people started working at the hospital, so it's impossible that they could have infected the children.

There seems to be political reasons why despite the scientific evidence the defendants may have been found guilty, but the defense attorneys do plan to introduce this newly found evidence on appeal, when there should be enough time to go over these findings, which only became available a week before the conviction.

In any case, evolution came to the rescue and sorted out this politically charged mess. How cool is that?

Source: Understanding Evolution