After an introduction giving an outline and the editor's view of population biology, the following selected topics are reviewed by five authors: (1) N. Takahata(National Institute of Genetics): Local Differentiation of Population and Differentiation of Species. (2) K. Ishii (College of General Education, Nagoya University): Population Genetical Mechanism of Molecular Evolution. (3) N. Yamamura (Department of Natural Science, Saga Medical School): Optimization Principle in Evolutionary Ecology. (4) M. Tanemura (Institute of Statistical Mathematics): Pattern of Territory and Mechanism of its Formation. (5) E. Teramoto (Department of Biophysics, Faculty of Science, Kyoto University): Population Size Distribution of Biological Communities.
It has been established that light stimulus depolarizes (invertebrate) or hyperpolarizes (vertebrate) photoreceptor cells by modulating the Na+ permeability of the cell membranes. The primary event in vision resides in a photon hitting the visual pigmellt, rhodopsin. However, the intermediate process linking rhodopsin bleaching to the opening or closing of the light dependent Na+ channel remains obscure. An effort to use Drosophila mutations for the study of this intermediate process is described. Two-dimensional gel electrophoretic analyses of a visual transduction mutation, norp A, suggested that three classes of retina-specific polypeptides in Drosophila and their light-dependent phosphorylation are involved in the visual process.