Allelic Interactions at the Shibire Locus of Drosophila: Effects on Behavior

Abstract

This report describes a detailed behavioral study of four shi alleles, shi^ts1, shi^ts2, shi^ts4, and shi^ST139, and their heteroallelic combinations. Flies of different heteroallelic combinations (shi/shi) were less sensitive to high temperature than the corresponding homozygotes. Among them, shi^ts2/shi^ts4 showed a striking reduction in temperature sensitivity. In contrast, different shi/+ heterozygotes were more severe in temperature sensitivity than the hemizygotes, Df/+. The hemizygous combinations of shi alleles over deficiency (shi/Df) were not completely lethal, with shi^ts2 conferring distinctively higher and shi^ts4 lower viability. A novel behavior, bang sensitivity, was also found in shi/Df. The results of allelic interactions suggest that the shi mutations examined appear to be antimorphic and that the shi gene products are likely to function in multimeric form.

Key Words:

• temperature-sensitive mutants
• bang-sensitive
• paralysis
• heteroallelic genotypes
• viability defects