Effective size of populations with heritable variation in fitness.

The effective size of monogamous populations with heritable variation in fitness is formulated, and the expression obtained is compared with a published equation. It is shown that the published equation for dioecious populations is inappropriate for most animal and human populations, because the derivation is implicitly based on the assumption that zygotes are produced by random union of gametes, each from conceptual male and female gametic pools. A convenient equation for practical use is proposed, and the application is illustrated with the estimation of the effective size of a rural human community in Japan.