THE INFLUENCE OF TEMPERATURE ON SYNAPSIS IN HYBRID SALIVARY GLANDS

¹ Department of Zoology, Hebrew University, Jerusalem, Israel

1. The effect of temperature on synapsis was studied in salivary glands of Drosophila pseudoobscura heterozygous for the Arrowhead inversion, and of D. melanogaster x simulans hybrids.

2. In the pseudoobscura larvae, significantly less asynapsis was observed at 17.5, 20 and 25° C. than at extreme temperatures (13 and 28° C.).

3. In the melanogaster x simulans hybrids, synapsis was most complete at 13 and at 25° C., and there were two significant peaks of asynapsis at 17.5 and at 31° C.

4. The common feature of the two distributions is the minimum of asynapsis at moderate (20 and 25° C.) temperatures. The possible relationships of this result with the known temperature effects on crossing over and on the position effect are discussed.