Exam 1 Flashcards
What is a trait?
An observable or measurable characteristic of an individual
What is an example of observable traits?
Appearance (coat color, horned, frame size)
What is an example of measurable traits?
Performance (weaning weight, yearling weight, scrotal circumference, milk yield, yield grade, quality grade)
What is phenotype?
Observed category or measure of performance for a trait of an individual
What are 2 examples of the difference between a trait and phenotype?
Phenotype: red Trait: coat color
Phenotype: 565 lbs Trait: weaning weight
What is genotype?
Genetic makeup of an individual
What do the letters in P=G+E mean?
Phenotype
Genotype
Environment
What is biological type?
Similar genotypes for traits of interest
When choosing the best animal, what makes up the system?
Genotype
Physical environment
Fixed resources and management
Economics
What are interactions?
A relationship where the effects of one component depends on another component
What is genotype by environment?
Different in performance between 2 or more genotype changes from environment to environment
In order to look at a G x E interaction, what must there be?
At least 2 genotypes and 2 environments
When looking at a graph, how do you know if there was an interaction?
If there was a swap in rank or change in magnitude
What are breeds?
Race of animals within species that have a common origin and similar characteristics
What are 4 examples of breeding objectives?
Carcass characteristics
Replacement females
Milk quality
Wool production
What is a population?
Group of intermating individuals
What are the 2 types of selection?
Natural
Artificial
What is natural selection?
Survival of the fittest
What is natural selection independent of?
Humans
What is an example of natural selection?
Hyperkalemic periodic paralysis
Parasite resistance
What is artificial selection?
Human control
What are some examples of artificial selection
Replacement
Culling
How is phenotypic selection done?
Through performance
How do we select the best breeding value? (4)
Measure performance
Information on relatives
Progeny
Genetic predictions
What is breeding value?
Value of the animal genetically and how it contributes in breeding
What are polygenic traits?
Traits made of many genes
What are simply-inherited traits?
Traits made of few genes
What are different matings and mating systems? (4)
Complementarity
Hybrid vigor/heterosis
Related individuals
Corrective matings
What is complementarity considered to be?
The best of both worlds
What are examples hybrid vigor/heterosis? (3)
Lines
Breeds
Species
What are examples of why you would use corrective matings? (2)
Frame size
Structure
How are quantitative traits measured?
By a bell curve
What are quantitative traits affected by?
Many genes
What is population mean denoted by?
μ
What is the sample mean?
Sum of all observations divided by sample size
What is variation?
How individuals vary for a particular trait in a population
What do variations in breeding values allow for?
Selection
What is variation described by?
Variance
σ^2
What is standard deviation?
The average deviation from the mean
σ
What percentage of the population does 1 standard deviation account for? 2? 3?
68%
95%
99%
Write the formula for variance. Check notes for answer equation 2
Write the formula for variance. Check notes for answer equation 2
How do you calculate standard deviation?
Square root of variance
What is covariation?
How 2 traits vary together
What are the 3 aspects of covariation?
Direction
Correlation
Regression
What are the 3 types of direction?
Positive covariation
Negative covariation
No covariation
What is positive covariation?
Positive deviations with positive deviations
What is negative covariation?
Positive deviations with negative deviations
What is zero covariation?
No pattern
Write the formula for covariance. Check notes for answer equation 3
Write the formula for covariance. Check notes for answer equation 3
What is correlation?
Strength of the relationship between 2 variables