GENETICS OF NATURAL POPULATIONS. II. GENIC VARIATION IN POPULATIONS OF DROSOPHILA PSEUDOOBSCURA INHABITING ISOLATED MOUNTAIN RANGES

Abstract

I N RECENT years there appears to be a growing interest in the genetics of free-living populations, a subject hitherto almost un- touched. Certain species of Drosophila prove to be very suitable for in- vestigations in this field. TSCHETWERIKOFF (CHETVERIKOV), DUBININ and their collaborators in Russia, TIMOFEEFF-RESSOVSKY in Germany, GORDON in England, and STURTEVANT in this country have secured much valuable information which opens new vistas and raises a host of new problems (for a short review of the literature see DOBZHANSKY 1937). It has seemed to us that a comparison of the genetic constitutions of several free-living popu' lations from the same general region, and yet isolated from each other, may be of interest. Samples of the populations of Drosophila pseudoob- scura inhabiting island-like mountain forests in the Death Valley region of California and Nevada were collected. This region is especially favorable for our purposes, since it is as yet practically undisturbed by man's activities.