The Inheritance of Jumping Activity in Reciprocal Cross of Two Subspecies of Mice

Abstract

The objective of this study was to describe the nature of the inheritance of jumping as a behavioral trait and to analyze quantitatively the jumping height as a measure of vigor in two subspecies of mice. Two subspecies of mice, Yonakuni wild mouse (Y) and CF#1 laboratory mouse (C), were used as the parental types. Reciprocal mating between these two subspecies was made to produce subsequently the first and second generations. The first generation was F1 (YC) resulting from Y male x C female, and F1’ (CY) from C male x Y female. The second generation F2 (YCYC) was from mating F1 x F1 and F2’ (CYCY) from F1’ x F1’. Individuals were treated with a set of direct current shock apparatus at six weeks of age to evoke jumping. The results showed that the ratio between jumping and non jumping mice (J: NJ) for C was 0%:100% (0:1), which means that all C did not jump throughout the experiment, whereas Y was 68%:32% (2:1); and the F1 and F2 showed 65%:35% (2:1) and 51%:49% (1:1), respectively. All F1’ and F2’ individuals jumped as indicated by the ratio 100%:0% (1:0) for both these two genetic groups. Of the jumped mice, average height of the first three jumping observed for pooled sexes in Y, F1, F2, F1’, and F2'' were 19.3 cm, 19.3 cm, 18.0 cm, 19.9 cm and 16.4 cm, respectively. The distribution of jumping height showed a tendency to be a normal distribution. The jumping activity and jumping height may be affected by some major genes and polygenes, respectively. Keywords : Jumping Inheritance, Reciprocal Cross, Subspecies of Mice