Abstract
Genetic analysis of Msp-1 (mouse salivary protein system-1) detected by polyacrylamide gel electrophoresis was conducted by mating experiments. In mating tests, two parental strains were used: C3H/He and BALB/c. The former showed S-type in the male and F-type in the female, while the latter showed F-type in both sexes. F1 males in reciprocal matings of C3H/He and BALB/c showed S-type and the segregate ratio of S and F-types in F2 males was 3:1. In backcrosses of BALB/c×F1, the segregate ratio of S and F-types in males was 1:1;however, all the females showed F-type. C3H/He males and F1 males changed from S-type to F-type after castration. The castrated males, C3H/He females and F1 females changed from F-type to S-type after testosterone administration. But both sexes of BALB/c remained as F-type after testoster-one administration. Based on the results, gene symbols Msp-1D and Msp-1O are proposed, desig-nating dominant sex dimorphism as in C3H/He and recessive no dimorphism as in BALB/c re-spectively. Msp-1 is considered to show sex-controlled inheritance under the control of autosmal dominant gene Msp-1D. Further, from the results of Tfm mice, sex dimorphism of Msp-1 is dependent on testosterone receptors for the means of protein assimilation.
