INHERITANCE OF GROWTH AND FORM IN THE MOUSE .4. CHANGES IN THE VARIANCE COMPONENTS OF WEIGHT, TAIL LENGTH AND TAIL WIDTH DURING GROWTH

  • 1 January 1979
    • journal article
    • research article
    • Vol. 43  (1) , 36-46
Abstract
A complete diallel cross, including inbreds and reciprocals, was made among 6 inbred lines of mice. Body weight, tail length and tail width were measured at ages of 1-12 wk. The analysis described by Griffing (1956a, 1956b, 1958) as the modified diallel, method 3, model II was made for each trait at each age and a separate analysis was made for each sex. Inbreds did not contribute to estimates of the effects in the diallel model, but were used to estimate heterosis. Positive heterosis was observed for all 3 traits. Heritability increased with age for all 3 traits, although it remained small for tail width; for body weight it was larger in females than for males, while for tail length and width the opposite was true. Non-additive genetic variance was observed for all 3 traits. Maternal effects variance was virtually non-existent for tail length, but for body weight and tail width it exhibited a marked peak around weaning, followed by a gradual decline for body weight and a rapid decline for tail width. Environmental variance exhibited a marked peak at weaning for all 3 traits and was larger for male body weight and tail length from 4 wk onward. Residual reciprocal effects were important for tail length at all ages, but were small or negligible for body weight and tail width. The relative importance of the individual''s genotype in determining size apparently increases with age, while that of non-genetic factors declines.