Viral Altruism
Bacteriophages are viruses that infect bacteria. It’s a tough business, as bacteria have sophisticated anti-phage defense systems which recognize and target invaders.
Phages counter with genes that encode proteins which stall the bacterial immune system. To implement these anti-defense viral genes, a phage must enter a bacterial host cell and thwart the immune response.
The virus cannot possibly survive this initial assault to reproduce itself. The virus knows this. The initial attack is a sacrifice gambit. The virus’ compeers will carry on to mount the bacteria’s protein-making machinery once its defenses are down.
This cooperation between genetically identical individuals of a viral population is altruism. ~ Israeli geneticists Rotem Sorek & Aude Bernheim
