Direct and maternal genetic effects on body weight maturing patterns in mice

Abstract

Direct and maternal genetic effects were evaluated for maturing patterns of body weight in mice using a crossfostering design. Crossfostering was performed in one group using dams from populations selected for rapid growth rate (M16 and H6) and their reciprocal F1. crosses. A second crossfostering group consisted of dams from the respective control populations (ICR and C2) and their reciprocal F1. 's. Population differences were partitioned into direct and maternal effects due to genetic origin, correlated selection responses, heterosis and cytoplasmic or sex-linked effects. Degree of maturity was calculated at birth, 12, 21, 31 and 42 days of age by dividing body weight at each age by 63-day weight. Absolute and relative maturing rates were calculated in adjacent age intervals between birth and 63 days. Genetic origin effects (ICR vs. C2; M16 vs. H6) were significant for many maturity traits, with average direct being more important than average maternal genetic effects. In general, correlated responses to selection for maturity traits were larger in the M16 population (M16 vs. ICR) than in the H6 population (H6 vs. C2) and correlated responses in average direct effects were larger than average maternal effects. Positive correlated responses in average direct effects were found for relative maturing rates at all ages and for absolute maturing rates from 31 to 63 days. Apparent correlated responses in degree of maturity were negative for M16 and H6. However, further analysis suggested that the correlated response for degree of maturity in H6 may be positive at later ages and negative at earlier ages. Direct and maternal heterosis for degree of maturity was positive in the selected and control crosses. Absolute and relative maturing rates showed positive heterosis initially, followed by negative heterosis. Reciprocal differences due to the cytoplasm or sex-linkage were not important for patterns of maturity.

Genetic and Physiological Aspects of Growth, Body Composition and Feed Efficiency in Mice: A Review

“…A number of researchers have reported significant heterosis for pre-and postweaning body weights and weight gains (Eisen, 1973;Bakker et al, 1976;Nagai et al, 1976). Williams et al (1978) observed significant heterosis for degree of maturity, absolute maturing rate and relative maturing rate at various pre-and postweaning ages.…”

“…Some researchers (Nagai et al, 1971;Eisen, 1973;Hayes and Eisen, 1979) have compared the performance of two or three lines of mice for direct and postnatal maternal genetic effects on weights and weight gains at different ages. A few attempts were made to partition the direct or correlated responses into direct and maternal genetic effects (individual and maternal additive) and direct and maternal heterosis (Eisen, 1973;Bakker et al, 1976;Nagai et al, 1976;Williams et al, 1978). In general, the results of these studies indicate that, although maternal genetic effects were significant at preweaning ages, the direct genetic effects were important at all ages.…”

Effects of genetic line and intake level on growth of mice: growth with ad libitum feeding

“…In crossfostering studies, EL OKSH et al (1967) and NAGAI (1971) reported that variation among postnatal dams accounted for 63 to 68 %, of the phenotypic variation in body weight of mice at 12 to 14 d of age. WILLIAMS et al (1978) also reported substantial maternal eftects on maturing patterns among selected mouse lines. These results suggest that the changes in growth patterns between intake lines may be related to changes in maternal ability.…”