Goto N, Fukuta K, Imamura K, Ohnishi A, Mikami H
Faculty of Agriculture, Kobe University, Japan.
Jikken Dobutsu. 1988 Jan;37(1):45-51. doi: 10.1538/expanim1978.37.1_45.
Morphometrical observations were carried out on the mandibles of chimeras made from the embryos of C57BL/6 and BALB/c mice to compare with the two strains and their reciprocal F1 crosses. The results of the principal component analysis indicate that the first principal component (PC1) and the second principal component (PC2) extracted might be acceptable as size and shape factors, respectively. Variations of both PC1 and PC2 were generally larger in the chimeras than in the two component strains and their F1 crosses. The mean PC1 value of the chimeras was larger than that of the two component inbred strains, and it was similar to that of F1 crosses, or slightly larger. The overall size of the mandible represented by PC1 tended to be larger in the chimeras consisting of two component cells that were approximately equivalent than in those that shifted to either cell population. The above trend was observed in both sexes. These results indicate that chimeric heterosis due to the interaction between genetically different cells (C57BL/6 and BALB/c) has some relation to mandible size. The mean PC2 value, which was accepted as shape factor, was intermediate between the two inbred strains. The mandible size (PC1) and shape (PC2) were bilaterally symmetrical, except for the shape in the female chimeras and in (C57BL/6 x BALB/c)F1.
对由C57BL/6和BALB/c小鼠胚胎制成的嵌合体的下颌骨进行了形态测量观察，以与这两个品系及其相互的F1杂交后代进行比较。主成分分析结果表明，提取的第一主成分（PC1）和第二主成分（PC2）可能分别作为大小和形状因素是可以接受的。嵌合体中PC1和PC2的变异通常比两个组成品系及其F1杂交后代中的变异更大。嵌合体的平均PC1值大于两个组成近交系的平均PC1值，与F1杂交后代的相似，或略大。由两个大致相等的组成细胞组成的嵌合体中，以PC1表示的下颌骨总体大小往往比偏向任何一个细胞群体的嵌合体更大。在两性中均观察到上述趋势。这些结果表明，由于基因不同的细胞（C57BL/6和BALB/c）之间的相互作用导致的嵌合杂种优势与下颌骨大小有一定关系。被视为形状因素的平均PC2值介于两个近交系之间。除了雌性嵌合体和（C57BL/6×BALB/c）F1中的形状外，下颌骨大小（PC1）和形状（PC2）是双侧对称的。
