Studies on the Bar Series of Drosophila Melanogaster. Ii. The Temperature-Effective Period for Facet Determination in Bar and Bar Vestigial

Abstract

I n an earlier paper of this series (MARGOLIS 1935), it was shown that the gene vg effected a small but significant decrease in facet nu&ers in Bar-eyed flies of Drosophila. The present paper deals with the results of an investigation of the temperature-effective period for facet determination in B and B vg stocks. The early investigations of SEYSTER (1919) and KRAFKA (1920) served to localize the temperature effect on facet number entirely within the larval period of development. More recently, DRIVER (1926,1931) and LUCE (1931) succeeded in setting more definite limits for the T.E.P. in B and Bi flies a t different temperatures. DRIVER, especially, has called attention to the necessity of precision in determining temperature-effective periods as a tool in analyzing the kinetics of facet determination in the Bar series. The results of these investigators will be discussed in greater detail in relation to the results obtained by the writer.For expediency, the temperature-effective period for facet determination will be referred to as the T.E.P.