[Genetic study of ovary development in Drosophila lutescens]

Experiments were carried out in order to clarify the genetic mechanism governing the development of ovaries of Drosophila lutescens female flies. Female flies of two strains obtained from northern (Niigata) and southern (Tokunoshima) parts of Japan, F1, F2, and backcrossed hybrids were examined. Female flies, one week after emergence at 14 degrees C, during which time they were kept under a 10 h 30 min light/13 h 30 min dark regimen, were dissected, and they were divided into three classes: those with mature, retarded, and undeveloped ovaries. The ratio of undeveloped ovary in the northern strain was much higher than that of the southern. From the results of all dissections, it is assumed that genes on chromosomes of the northern strain operate to stop ovarian development and that cytoplasmic factors of the southern strain act to suppress those genes. It may be, therefore, suggested that the development of the ovary of this species before hibernation is controlled genetically.