Immunosenescence and human longevity

Abstract

Humans are almost certainly the longest-living of all mammals. What explains their longevity? Are there evolutionary pressures favouring longer life and if so what are they? If longevity is a positively selected trait, are many or few genes responsible for this characteristic? It is proposed here that human longevity was selected for at the level of relatively few genes and that many of these are involved in regulating the immune system.