[The temperature dependence of selection efficiency and the expression of the genes controlling the rate of embryonic development in Drosophila melanogaster].

We have already shown that selection of heterogeneous D. melanogaster populations for the rate of embryogenesis at 32 degrees C may produce populations, in which 50% of the larvae are hatched 20-40 min earlier, i.e., 2-4% more rapidly than, in the control. Highly inbred strains were obtained from the selected populations and develop 5-7% more rapidly than the control populations. Here we studied separately the effects of temperature on the efficiency of selection and expression of the selected genotype. With this in view, multiple (9-15 rounds) selection of the first 10% of the larvae was performed at 17, 25, and 32 degrees C and the mean duration of embryogenesis (hatching of 50% larvae) at these three temperatures was determined in the entire selected population. Selection proved to be almost equally efficient at all temperatures. On the contrary, expression of the selected genotypes markedly depended on temperature: the rate of embryogenesis of the selected populations exceeded that in the control at 17 degrees C by 1.1%, at 25 degrees C by 2.5%, and at 32 degrees C by 3.5%. In the inbred strains this dependence was even more pronounced: 1.2%, 2.7%, and 5.7%, respectively. The temperature dependence of expression of the genes collected by selection and coding for accelerated development means that these genes affect the rate of development as the function of temperature by changing the angle of the curve inclination. Possible mechanisms of this phenomenon are discussed.