Question: What specifically are suicide genes and how do they work in bacteria?

Juan Ortiz answered on 20 Jun 2016:

Suicide genes are genes responsible of the programmed cell death or apoptosis. This is a very important process because controlled cell death is necessary when some cells are defective or for the development of some organs (the loss of the primitive tail in human embryos for example). In other words, cells are programmed to sacrifice themselves when necessary for the good of the organism. However, some cells become defective and do not respond to the suicide commands. So they continue growing abnormally and generate more cells like themselves getting out of control and invading other parts of the body. That is how the tumors appear.

In bacteria there is also a system of suicide. It was a shock for me when I read for first time about the suicide genes in bacteria. These genes codify a toxin lethal for the bacteria and an anti-toxin capable of neutralise the toxin. But why a bacteria (made only by one cell) wants to suicide? What is the advantage if bacteria are not part of a bigger organism? This is the answer: bacteria usually divide quickly generating a big a population of genetically identical bacteria (clones). If there are problems like lack of nutrients, the suicide of some of them may help the others (which are genetically identical) to get more nutrients, since now they don’t have to compete for them with so many bacteria.