Stutts - ANSC 4395 Breeding & Genetics - Test 4 QUESTIONS WITH COMPLETE ANSWERS

Stutts - ANSC 4395 Breeding & Genetics - Test 4 QUESTIONS
WITH COMPLETE ANSWERS
Phenotype Correct Answer: the outward appearance of an individual P=G+E

Genetic Effects categories Correct Answer: additive effects - A
dominance effects - D
epistatic effects - genes at two different loci - I

Additive gene action - codominance Correct Answer: each dominant allele gets +2
AA - +4
Aa - +2
aa - 0

Additive gene action - complete dominance Correct Answer: BB - +4
Bb - +4
bb - 0

Epistasis Correct Answer: interaction among genes at multiple loci
I in the equation P = A + D + I + E

Environmental component of equation Correct Answer: temporary environmental effect - Et
permanent environmental effect - Ep

Temporary environmental effects Correct Answer: sources of environmental variation that have
somewhat of a temporary effect
disease, weather, changes in management

Permanent environmental effects Correct Answer: changes the way an animal performs for the
rest of its life
failure to have calf, severe illness, injury to udder

Phenotypic Variance Correct Answer: the sum of the variances of all genetic and environmental
effects

If there is a normal distribution of phenotypes Correct Answer: there is a normal distribution of
additive effects, dominance effects, epistatic effects, permanent environmental effects, and
temporary environmental effects

Heritability Correct Answer: the proportion of the phenotypic variation which is due to additive
gene effects
most important sing concept in animal breeding**
only additive effects are passed on to offspring

used to estimate breeding value and predict response to selection