[The effect of prolonged exposure to heat on the activity of salivary gland polytene chromosomes].

The influence of long-term heating on the puffing activity of polytene chromosomes in the early prepupa salivary glands was investigated. The activity of puffs was estimated by two criteria: size and frequency. The rearing of insects at a temperature of 29 degrees resulted in puff changes: the activity of some puffs increased or depressed, some puffs were inhibited, other puffs were induced newly. The differential response of each chromosome was observed. A possible mechanism of the effect of heating on the puff activity of polytene chromosomes is discussed.