Genetic Conflict and Apoptosis

The benefits of apoptosis in the removal of unnecessary, damaged, or dangerous cells are dependent on the altruism resulting from the absence of genetic conflict between genes in cells. However, this altruism can be exploited by self-promoting or ultra-selfish genes. These self-promoting genes can be endogenous, as with neoplasia or germ cell mutations, or exogenous, as with cellular pathogens. The fundamental flaw of apoptosis is that its development and maintenance as a system is constantly opposed by the emergence of self-promoting genes. Since apoptotically impaired cells cannot be relied on to kill themselves, apoptotic input from other cells is required for controlling self-promoting genes. Certain unique features of germ cell development, such as linkage by cytoplasmic bridges and the requirement for granulosa or Sertoli cells, appear to serve this requirement for control of self-promoting genes.