Effect of inbreeding and selection on fertility and growth in mice

The experiment comprised 3 lines of outbred mice: An inbred line without se lection (1), an inbred line with selection (2) and a non inbred control lin e with random mating (3). In line I and 2 half sister mating was used. In l ine 2, 20% of the females are selected for litter size and stillbirths of t heir darn. The males are selected at two stages; 50% for body weight at the age of 10 days and 50% for body weight at the age of 21 days. Inbreeding d epressions seems to depend non linear on the degree of inbreeding. Selectio n within the line 2 could compensate inbreeding depression for fertility an d growth, Epistatic effects and natural selection are discussed as a cause of the non linear inbreeding depression.