Livestock Breeding and Genomics - Exercise 2

Problem 1: Breeding Values For a Monogenic Trait

We assume that the absorption of cholesterol is determined by a certain enzyme. The level of enzyme production is determined by a single bi-allelic locus \(E\). The genotype frequencies and the genotypic values for the two dairy cattle populations Original Braunvieh and Brown Swiss are given in the following table.

Variable	Original Braunvieh	Brown Swiss
f(E1E1)	0.0625	0.01
f(E1E2)	0.3750	0.18
f(E2E2)	0.5625	0.90
a	15.0000	29.00
d	3.0000	0.00

Hints

• Assume that allele \(E_1\) is the allele with the positive effect on the enzyme level
• Assume that the Hardy-Weinberg Equilibrium holds in both populations

Your Task

Compute the breeding values for all three genotypes in both populations.

Your Solution

Problem 2: Quantitative Genetics

In a population the following numbers of genotypes were counted for a given genetic locus called \(A\).

Genotypes	Numbers
A1A1	24
A1A2	53
A2A2	23

1. Compute the genotype frequencies

2. Compute the allele frequencies

3. Compute the population mean \(\mu\) under the following assumptions

• the difference between the genotypic values of the homozygous genotypes is \(20\) and
• the genotypic value of the heterozygous genotype is \(2\).

Your Solution