Polygenic Inheritance
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Breeders Assistant handles not only discrete traits - i.e. traits where it is known that specific alleles of known genes form the mode of inheritance - but also polygenic traits. A polygenic trait is one where it is thought that many genes control a trait, and it is the 'quantitative sum' of the 'values' of those genes that define the degree to which the trait is expressed.
Such polygenic traits typically show a continuous range of expression. This mode of inheritance applies to many of the most important characteristics breeders need to focus on in a breeding program. E.g. traits such as head shape in cats ('type') are polygenic in nature and improvement requires careful breeding selection and outcrossing over extended generations.
For the first time in a 'breeders' pedigree program, Breeders Assistant introduces modelling of polygenic traits. A trait can be defined with a series of grades - a grade being a range of values. E.g. in BA for Dogs we can model hip dysplasia using either the OFA or BVA grading schemes. With the OFA scheme (as used in America), the grades are:
Severe Hips. (0-1)
Moderate Hips. (1-2)
Mild Hips. (2-3)
Borderline Hips. (3-4)
Fair Hips. (4-5)
Good Hips. (5-6)
Excellent Hips. (6-7)
With the trait defined, you can then assign values for that trait to individual animals. BA can use this data in various ways:
Estimate the likeliest value of a trait in an individual based (entirely) on the known polygene values of its ancestors. Click here for details.
Compute covariance for polygenic traits - both between traits and between relatives. Click here for details.
Another thing you can do is a Polygenic Family Analysis. This is where BA will compute stats on given polygenes for all animals with a given familial relationship e.g. full sibs, half sibs, sire-side sibs etc. This can be a useful selection aid.
See Also:
Genetics Overview
Entering Genotypes
Comprehensive Cat Genetics
Comprehensive Dog Genetics
Inbreeding & Common Ancestors
Mating Predictions
Gene Inheritance Probabilities
Genetic Configuration Files
Genotype Verification
Covariance Analysis
Gene Frequency Analysis
This feature requires the Genetics Option.
