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Genetic Evaluation and Breeding Program Design

Current Version

GENE 422-522 was originally issued in 2007. It was created with funding provided by the Sheep CRC supported by MLA and AWI. UNE, charged with creating the unit, initially presented the material with lecture notes in DOC and PDF format, and included copies of many of the references appended to the lectures. Presentations in Powerpoint format were also provided for each topic.

The module was revised in 2011, although these updates were relatively minor. Consequently, the PPT files that were available have also been retained and can be downloaded as a compressed archive. The major change is the addition of an appendix on matrices.

A revision was released in 2023 and this is the current version.

The module consists of 21 topics.  See Topic 0 for Table of Contents.

Topic 0: Genetic Evaluation and Breeding Program Design – Table of Contents 

Topic 1:  Introduction to Breeding Programs

On completion of this topic you should be able to:

• Understand the different aspects involved in breeding programs
• Analyse (animal) breeding programs as a logical order of decisions to be made
• Put the different aspects of breeding in the right context, and understand the knowledge needed about making certain investments

Topic 2: Principles of Estimating Breeding Values

On completion of this topic you should be able to:

• Understand the principle of estimation of breeding value (EBV)
• Understand why EBV is a better predictor of genetic merit of offspring than an animal’s own phenotype
• Understand accuracy of EBV
• Predict how much EBVs vary among individuals
• Predict how much EBV might change with new information
• Predict response to selection based on EBV

Topic 3: Selection Index Theory: Information from Relatives

On completion of this topic you should be able to:

• Assess the value of relative’s information in EBV accuracy
• Derive the weights on relative’s information in estimating breeding value
• Understand the value of progeny testing
• Know the relationship between progeny test size and accuracy of sire’s EBV

Topic 4: Linear and Mixed Modules

On completion of this topic you should be able to:

• Understand the power of linear models
• Set up a simple example of linear models
• Understand the principle of mixed models
• Understand how in BLUP, different effects can be taken into account
• Understand how BLUP uses additive genetic relationships
• Know that BLUP uses optimal selection index weights for the different sources of information to estimate the breeding value of an animal

Topic 5: Best Linear Unbiased Prediction

On completion of this topic you should be able to:

• Understand how BLUP accounts for selection of parents and non-random mating
• Understand how BLUP can estimate genetic trends
• Calculate accuracy from mixed model equations
• Understand accuracy from BLUP-EBV, in particular in relation to the contemporary group size and the ‘effective information’ about each animal.
• Understand the effects of BLUP selection on genetic progress and inbreeding
• Understand the level of complexity of commercial genetic evaluation programs
• Understand the requirements about data quality and the models used for genetic evaluation
• Know about the different extensions that are possible based on the animal model
• Understand across breed evaluation

 

Topic 6: Estimation of Genetic Parameters

On completion of this topic you should:

• Understand the importance of estimation of genetic parameters in animal breeding
• Know when estimation of genetic parameters may be required
• Understand the principles of estimation of variance components
• Estimate heritability from sib analysis
• Estimate heritability from parent-offspring regression
• Be aware of the different methods that can be used to estimate genetic parameters

Topic 7: Molecular Marker Associations

On completion of this topic you should have an understanding of:

• Molecular markers detect variation at the DNA level
• Markers can be used to detect Quantitative Trait Loci (QTL)
• Linkage and linkage disequilibrium
• Statistical considerations for marker choice for QTL detection and mapping
– Experimental design: When can we expect an association between a marker
genotype and a QTL?
– Statistical: What are the chances to find a QTL, and what does this depend on?
– Understand the issues of multiple testing in QTL detection

Topic 8: Genomic Selection and Prediction

On completion of this topic you should be able to:

• Understand what genomic selection involves
• Understand when genomic selection can be useful
• Understand what factors make genomic selection more accurate
• Understand how EBV can be calculated with the knowledge of genomic information

 

Topic 9: Breeding Objectives

On completion of this topic you should be able to answer the following questions:

• What is a breeding objective?
• Why is it important to define the breeding objective?
• How is the breeding objective used for selection of animals?

Topic 10: Multiple Trait Selection

On completion of this topic you should know:

• How to derive selection criteria for multiple traits
• How to predict multiple trait selection response
• How to manipulate multiple trait selection response
• Considerations in order to make optimal genetic change

Topic 11: Breeding Program Design Principles

On completion of this topic you should be able to:

• Understand the issues involved in breeding program design
• Predict rates of genetic improvement for breeding programs
• Design and compare alternative breeding programs

Topic 12:  Balancing Selection and Inbreeding

On completion of this topic you should:

• Have a good understanding of the concept of inbreeding
• Understand the need for balance between genetic gains and inbreeding
• Understand the tactical approach to solving this issue

Topic 13: Summary

On completion of this topic you should:

• Be able to put together the different topics from this unit in a unifying framework
• Understand the place of each topic of this unit in the context of an animal breeding program
• Be able to analyse an animal breeding problem in a breeding program context, and to know the
tools available to help implementing such programs
• Understand new developments and evaluate them in the right context

Topic 14: Mixed Models for Genetic Evaluation

On completion of this topic you should be able to:

• Understand some of the complexity of models used in commercial genetic evaluations
• Know about the different extensions that are possible based on the animal model
• Understand across breed evaluation
• Understand the benefits of multiple trait genetic evaluation and when it is mostly advantageous
• Understand how multiple trait mixed models are set up and have an idea about computational aspects
• Understand the importance of correct genetic parameters

This topic is rather detailed and gives some technical information on how to work out a more complicated mixed model. This is useful for people that need to code up BLUP evaluations. The
principles of the more advanced BLUP models have been presented in Topic 5. Technical detail was also presented in Topic 5.

Topic 15: Estimation of Genetic Parameters – More Detail

On completion of this topic you should:

• Understand the importance of estimation of genetic parameters in animal breeding
• Know when estimation of genetic parameters may be required
• Understand the principles of estimation of variance components
• Estimate heritability from sib analysis
• Estimate heritability from parent-offspring regression
• Be aware of the different methods that can be used to estimate genetic parameters

Topic 16: Designs to Exploit Reproductive Technology

On completion of this topic you should:

• Have an understanding of the different reproductive technologies available to animal breeders
• Have an understanding of how each technology can affect genetic progress

Topic 17: Breed Utilisation and Crossbreeding 

On completion of this topic you should:

• Understand the issues that affect which is the best crossing system to adopt
• Have a good feel for what makes dominance good and epistasis bad in crossing systems

Topic 18: Breeding Practices in the Merino Industry

On completion of this topic you should understand:

• The structure of the commercial and ram breeding sectors of the industry
• The traits which influence production and how to include them in a breeding objective
• Merino genetic evaluation and breeding systems

Topic 19: Breeding Practices in the Lamb Industry

At the end of this topic you should:

• The structure of the commercial and ram breeding sectors of the industry
• The traits which influence production and how to include them in a
breeding objective
• Understand and describe the way in which Sheep Genetics has improved sheep meat production
• Understand the relevance of genetic correlation to ASBV
• Be able to separate environmental from genetic effects
• Understand the measures of accuracy for ASBV and FBUS

Topic 20: Practical Breeding Program Issues – Beef Industry

On completion of this topic you should be able to:

. Demonstrate understanding of the structure of the beef industry, and its impact on genetic improvement
. Demonstrate understanding of the three primary components of genetic improvement (breeding objectives, genetic evaluation and breeding program design)
. Discuss relevant issues associated with these key components in the beef industry
. Appreciate and discuss the tools available for genetic improvement in the beef industry, and have used their web applications.
. Discuss uptake of genetic technology in the beef industry
. Discuss future developments in genetic improvement in the beef industry

Topic 21: An Introduction to
Matrix Algebra and Linear Models

Matrices take a lot of the tedium out of both presenting algebra and
calculating results. They are widely used in scientific animal breeding,
particularly in selection indices and BLUP.