The Altruism Equation

"...Hamilton’s eponymous rule, rb > c, states that altruistic behavior will evolve if the coefficient of relatedness (r) between benefactor and beneficiary organisms multiplied by the benefactor’s fitness benefits (b) exceed the costs (c) to the benefactor. Simply put, since one’s genes are shared with one’s relatives, enhancing relatives’ reproductive success is a way for genes to proliferate themselves. From this perspective, unselfish behavior can be the upshot of "selfish" genetic strategies (although depriving myself of food so that my children can eat looks selfless, on the genetic level it is quite self-serving). My genes don’t give a damn how they get replicated; their only "concern" is that they get replicated..."

The Altruism Equation: Seven Scientists Search for the Origins of Goodness.

Lee Alan Dugatkin.