Phenotypic response to selection for traits with direct and maternal components when generations overlap.

Area of Science:

• Quantitative genetics
• Animal breeding and genetics

Background:

• Traits in livestock and other populations often exhibit both direct genetic effects and maternal genetic/environmental effects.
• Accurate prediction of selection response requires accounting for these complex inheritance patterns across generations.

Purpose of the Study:

• To develop and describe a method for predicting selection response in traits influenced by direct and maternal components.
• To account for discrete and overlapping generations in selection response predictions.
• To investigate the impact of environmental correlations between direct and maternal effects.

Main Methods:

• The expected phenotypic response is calculated as the sum of direct and maternal contributions.
• Maternal contributions include both genetic and environmental components.
• Selection differentials are incorporated into updated age-sex distribution vectors for overlapping generations.

Main Results:

• The prediction method accounts for direct genetic, maternal genetic, and maternal environmental effects.
• Overlapping generations are handled by updating age-sex distributions with selection information.
• Environmental correlations between direct and maternal effects can significantly influence early selection results.

Conclusions:

• The described method provides a framework for predicting selection response in traits with direct and maternal effects.
• Accurate interpretation of phenotypic changes in selected populations requires considering maternal effects and their environmental correlations.
• This approach is valuable for optimizing breeding programs in animal populations exhibiting maternal influences.