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Cytoplasmic effects on selection response for increased growth rate in mice
R M Petters1, E J Eisen, D Pomp
1Dept. of Anim. Sci., North Carolina State University, Raleigh 27695-7621.
Journal of Animal Science
|February 1, 1988
Summary
Mitochondrial DNA (cytoplasmic effects) did not significantly impact long-term selection for mouse growth rate. Only 4-week body weight showed a minor difference, suggesting nuclear genes are primarily responsible for growth improvements.
Area of Science:
- Animal Genetics
- Developmental Biology
- Quantitative Genetics
Background:
- Long-term selection experiments aim to understand genetic basis of traits.
- Cytoplasmic inheritance, via mitochondrial DNA, can influence complex traits.
- Investigating cytoplasmic effects is crucial for fully understanding selection response.
Purpose of the Study:
- To ascertain the contribution of cytoplasmic effects to selection response for growth rate in mice.
- To differentiate between nuclear and cytoplasmic influences on postweaning weight gain.
Main Methods:
- Reciprocal cross matings between selected (M16) and control (ICR) mouse lines.
- Embryo transfer to standardized pseudopregnant foster mothers to control uterine and maternal environments.
- Measurement of body weight, weight gain, organ weights, and reproductive traits.
Main Results:
- A significant difference (P < .05) in 4-week body weight was observed, favoring mice with ICR cytoplasm.
- No other significant differences were detected in growth traits, organ weights, or litter size between reciprocal crosses.
- Mitochondrial DNA did not appear to influence direct or correlated responses to selection for weight gain.
Conclusions:
- Cytoplasmic effects, as mediated by mitochondrial DNA, played a minimal role in the long-term selection response for increased postweaning weight gain in this mouse model.
- Nuclear genetic factors are likely the primary drivers of the observed selection response for growth rate.