Mathematical Proceedings of the Cambridge Philosophical Society

Research Article

A Mathematical Theory of Natural Selection. Part VIII. Metastable Populations

Mr J. B. S. Haldanea1

a1 Trinity College

Almost every species is, to a first approximation, in genetic equilibrium; that is to say no very drastic changes are occurring rapidly in its composition. It is a necessary condition for equilibrium that all new genes which arise at all frequently by mutation should be disadvantageous, otherwise they will spread through the population. Now each of two or more genes may be disadvantageous, but all together may be advantageous. An example of such balance has been given by Gonsalez(1). He found that, in purple-eyed Drosophila melanogaster, arc wing or axillary speck (each due to a recessive gene) shortened life, but the two together lengthened it.

(Received November 20 1930)

(Accepted December 08 1930)