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Genetic correlation and response to selection in simulated populations : I. Additive model
R J Parker1, L D McGilliard, J L Gill
1Michigan State University, East Lansing.
Summary
Truncation selection on a primary trait can decrease genetic correlation with a secondary trait, especially with high heritability and low selection intensity. This effect was observed over 30 generations in simulated populations.
Area of Science:
- Quantitative Genetics
- Animal Breeding
- Population Genetics
Background:
- Genetic correlation influences the correlated response between traits during selection.
- Understanding how selection affects genetic correlations is crucial for effective breeding programs.
Purpose of the Study:
- To examine the impact of truncation selection on a primary trait's genetic correlation with a secondary trait.
- To investigate the influence of selection intensity, heritability, and population size on this relationship.
Main Methods:
- Computer simulations of genetic populations over 30 generations.
- Additive gene action with 48 independently segregating loci per trait.
- Varied genetic correlations, selection intensities, and environmental variances.
Main Results:
- Genetic correlations remained stable when half of offspring were selected as parents.
- When only one-fifth of offspring were selected, genetic correlations decreased, particularly with high heritability after 15 generations.
- The reduction in genetic correlation was more dependent on the heritability of the selected trait than the selection intensity.
Conclusions:
- Truncation selection can erode genetic correlations between traits, impacting correlated responses.
- Heritability of the selected trait is a key factor in the magnitude of genetic correlation reduction.
- Estimates of genetic correlation in small simulated populations can be unreliable.
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