近交系ならびにその正逆交配からえられたF1マウスにおける骨格の変異
1964 年 13 巻 1 号 p. 1-7
詳細
1964 年 13 巻 1 号 p. 1-7
Skeletal variations in the various strains of mice (C57BL/6HeMs, CF#1, RF, and C3H/AnHeMs) and their F1 hybrids which were produced by reciprocal crosses of three inbred strains (C57BL/6, CF#1, and RF) were demonstrated. These strains were bred and maintained by the sister-brother matings since 1960 in the Natonal Institute of Radiological Sciemces. Examined bones are followings: interfrontal bone, cervical vertebrae, thoracic vertebrae and ribs, lumber vertebrae, sacral vertebrae, and caudal vertebrae. The same analysis was carried out further with the ICR-JCL mice which were bred and supplied in the Central Laboratories for Experimental animals. The data obtained were presented in Table 1-6.
Frequency of “interfrontal bone” was higher in C57BL/6 and RF strains (about 27%), and lower in others. The cervical vertebrae were 7 in all strains and their F1 hybrids. The fusion between cervical vertebrae (other than atlas-axis fusions) was seen frequently in the C57BL/6 (31% in all specimens of the C57BL/6), but none was found in ohers. Variations in thoracic vertebrae and ribs were found in CF#1 (17%), RF (7.1%), and ICR (6.1%) . These variations included the 1314, 1413, and 14 thoracic vertebrae (i. e. rib-bearing) . Other strains of mice kept always 13 thoracic vertebrae without variations.
The lumber vertebral numbers of C3H, ICR, and RF were predominantly 6. On the other had, the mice with 5 lumber vertebrae were appeared in the C57BL/6 (20.5%), CF#1 (13.8%), (C57BL/6 × CF#1) F1 (15.3%), and (C57BL/6 × RF) F1 (11.1%) with compared to the other strains and their F1 hybrids.
Two types were obseved with the pattern of sacral vertebrae : 4 bone-fused type and 3 bone-fused one. The former was found in the CF#1 (100.0%), C3H (96.5/), RF (94.4%), and ICR (67.7%), the latter was found frequently in C57BL/6 (58.9%), and the F1 mice from C57BL/6 males and females. Caudal vertebral numbers of the adult mice were distributed between 27 and 35. The largest numbers were found in the ICR and the smallest were observed in the C3H and C57BL/6 strains of mice.
