Abstract:

Chymotrypsin inhibitor (CI) in Bombyx mori may play important roles in its normal development and growth with rich polymorphsim. In the experiment the distribution of CI polymorphsim in hemolymph among 425 silkworm strains was investigated by nativepolyacrylamide gel electrophoresis (Native-PAGE). The results indicated that three genes  Ict-E,  Ict-Dand Ict-Aexpressed in every strain, suggesting that these genes should be necessary for the development of silkworm, and the products of genes Ict-H and Ict-B were not found in 9 strains, which had no distinct deficiency in development. The polymorphsim distribution of CI exhibited the similar pattern in both the Japanese and Chinese strains. Finally, the cluster analysis of the CI polymorphsim distribution in 52 pure strains showed that the clustered groups were not correlative to the strain system, moltinism or voltinism. It was so concluded that CI existed commonly n different strains of silkworm, and the characteristics of CI polymorphsim distribution suggest that differentiation of their function may have occurred in evolution.

Key words: Bombyx mori, strains, hemolymph, chymotrypsin inhibitor, polymorphsim distri