Abstract
Chromosomal polymorphism in natural populations of Drosophila lutescens, a semidomestic species, were studied. Chromosomal variations in six natural populations and thirty local strains maintained in laboratory culture were examined. In all populations remarkable inversion polymorphism was observed in four arms of the second and the third chromosomes. It was shown that there were clinal changes in the frequency of some gene arrangements (2L A, 3L A, 3L C and 3R D) from north-east to south-west in Japan. It is assumed that the main factor controlling the inversion frequencies is temperature.
