A set of rules for deciding which males are mated to which females
A polygenic trait is:
A trait affected by one gene
A trait that is expresses using numbers
A trait that is expresses in categories
A trait affected by many genes
When _____ gene action is expressed, the performance of the heterozygote is exactly between the expression of the homozygote
When _____ gene action is expressed, the performance of the heterozygote is identical to the dominant homozygote.
When _____ gene action is expressed, the performance of the heterozygote is outside the range of the two homozygotes
Epistasis is a phenomenon in which:
Parental genes are randomly sampled
Expression of the heterozygote is not exactly intermediate to the two homozygotes
Phenotypic expression is limited to one sex
Genes from different loci interact to affect the expression of a phenotype
The X and Y chromosomes are referred to as:
Which mode of inheritance refers to phenotypic expression that occurs in only one sex?
How do we refer to the pattern of inheritance for genes located on the sex chromosomes?
Which mode of inheritance refers to gene expression that is different in males vs. females?
Consider a hypothetical locus for resistance/susceptibility to the PRRS (porcine respiratory and reproductive syndrome) virus with alleles Pr and Ps. When exposed to the PRRS virus as a young age, PrPr individuals survive 85% of the time while PsPs individuals survive 25% of the time. What is the value of survival percentage for PrPs individuals if the locus exhibits additive gene action?
Consider a hypothetical locus for resistance/susceptibility to the PRRS (porcine respiratory and reproductive syndrome) virus with alleles Pr and Ps. When exposed to the PRRS virus as a young age, PrPr individuals survive 85% of the time while PsPs individuals survive 25% of the time. What is the range of values of survival percentage for PrPs individuals if the locus exhibits incomplete dominance and Pr is the dominant allele?
55% to 85%
Greater than 85%
25% to 55%
Less than 25%
Consider a hypothetical locus for resistance/susceptibility to the PRRS (porcine respiratory and reproductive syndrome) virus with alleles Pr and Ps. When exposed to the PRRS virus as a young age, PrPr individuals survive 85% of the time while PsPs individuals survive 25% of the time. What is the range of values of survival percentage for PrPs individuals if the locus exhibits over-dominance and Ps is the dominant allele?
The definition of a gene frequency is:
Frequency of a single locus genotype with a population
frequency of a single locus within an individual
Frequency of a given allele within an individual
Frequency of a given allele within a population
Within a given population, 92 individuals are BB, 123 individuals are Bb, and 145 individuals are bb. What is the total number of alleles at this given locus?
Within a given population, 92 individuals are BB, 123 individuals are Bb, and 145 individuals are bb.
What is the genotypic frequency for the Bb genotype?
Which of the following is NOT a condition of the Hardy Weinberg law?
Low Mutation Rate
Randomly Mating Population
Assuming all of the conditions of the Hardy Weinberg law have been met and the parental allele frequencies are pM = 0.25 and pm = 0.75 at the M locus, what is the expected frequency of the Mm genotype in the progeny?
What effects do mutations have on a population?
increase the amount of genetic variance in the population
lower the frequency of favorable alleles in the population
decrease the amount of genetic variance in the population
increase the frequency of favorable alleles in the population
Which of the following factors increases the amount homozygosity within a population?
Within a given population, 92 individuals are BB, 123 individuals are Bb, and 145 individuals are bb. What is the frequency of the b allele at this locus?
Within a given population, sires have allele frequencies of pA = 0.64 and qa = 0.36 at the A locus. Dams have allele frequencies of pA = 0.52 and qa = 0.48 at the A locus. What is the expected frequency of the Aa genotype in the progeny of these sires and dams?
Given the following information, what is the gene frequency of the Y allele in this population?
Which of the following is NOT a result of inbreeding?
Increase the likelihood of homozygotes in the population
Increase overall genetic variance within the population
Increased expression of deleterious recessive alleles
Increased phenotypic uniformity among relatives
A decrease in population performance following an increase in the number of homozygotes and reduction of genetic variance in a population is called:
An individual’s value as a parent is known as
The predicted breeding value for the offspring created from a single mating is calculated as:
P = µ + G + E
BV= 1/2PD =1/2PD
BV (offspring)= 1/2 BV sire= 1/2 Dam
P offspring= mew = 1/2BV sire=1/2BVDam + E
Traits for which animals typically have more than one performance record are:
Simply Inherited Traits
Which of the following values contains BOTH genetic and environmental components
Gene Combination Value
Which of the following is an estimate of a population measure?
Calculate the sample mean of the following weaning weight data (lb.).
Calculate the variance for the following set of data (in.).
The mean for a given set of data was calculated to be 64.56cM. The variance was calculated to be 306.25cM2. What is the standard deviation for this dataset?
The mean for a given dataset was calculated to be 10.75lbs. The variance was calculated to be 12.25lbs2. What is the range of values for which you would expect 95% of the population to fall in?
Which of the following represents the correct unit(s) to express a covariance between loin muscle depth (in.) and mature weight (lb.) in pigs?
None of the above
In a sampling of cattle from a large population, the average birth weight is 72lb. and the average yearling weight is 772lb. The standard deviation for birth weight is 9.5lb and the standard deviation for yearling weight is 57lb. The covariance that was calculated for the two traits is 216lb•lb. What is the phenotypic correlation for this trait?
The measure of the strength of the relationship between breeding values for one trait and breeding values in another trait are known as _________:
In a sampling of cattle from a large population, the average birth weight is 72lb. and the average yearling weight is 772lb. The variance for birth weight is 90.25lb2 and the variance for yearling weight is 3249lb2. The covariance that was calculated for the two traits is 216lb•lb. Calculate the regression coefficient for a regression of birth weight on yearling weight.
Which of the following is NOT a measure that encompasses information from two separate traits
In a sampling of pigs from a large population, the average birth weight is 3.461lb and the average weaning weight is 46.603lb. The variance for birth weight is 0.1017lb2 and the variance for weaning weight is 20.5416lb2. The covariance that was calculated for the two traits is 1.3314lb•lb. Calculate the regression coefficient for a regression of weaning weight on birth weight.
What is the possible range for a covariance?
0 to 1
-1 to 1
0 to 100%
There is no range
In a sampling of cattle from a large population, the average weaning weight (WW) is 464lb and the mean average daily gain (ADG) is 2.53lb/day. The regression coefficient for weaning weight on average daily gain 43.59lb per 1lb/day. Predict what the weaning weight of an animal that has an average daily gain of 2.67lb/day.
the relationship between the phenotypic values and the permanent environmental effect for a given trait
the relationship between the breeding values and the environmental effects for a given trait
the relationship between the phenotypic values and the breeding values for a given trait
the relationship between the breeding values and producing abilities for a given trait
the relationship between the breeding values and the producing abilities for a given trait
the relationship between the phenotypic values and producing abilities for a given trait
Adjusting milk yield phenotypes by the age of the cow would improve our heritability estimate by:
decreasing environmental variance, thus reducing the overall phenotypic variance
decreasing breeding value variance, thus reducing the overall phenotypic variance
increasing environmental variance, thus increasing the overall phenotypic variance
increasing breeding value variance, thus increasing the overall phenotypic variance
Given the following information, calculate the heritability of this hypothetical trait:
σ2BV = 21.45 σ2GCV = 14.92 σ2E = 47.81
Given the following information, calculate the repeatability of this hypothetical trait:
σ2BV = 21.45 σ2GCV = 14.92 σ2Ep = 12.64 σ2Et = 35.17
Which of the following statements about heritability is NOT true?
The range for heritability is 0 to 1.
It is very difficult to make genetic progress in a trait that is highly heritable.
Heritability can vary from generation to generation within a population.
Relatives tend to resemble each other in traits that are highly heritable.
Which of the following statements can describe a contemporary group?
A group of animals that have experienced similar management practices.
A group of animals that are in the same location
A group of animals that are similar in age
All of the above
Which of the following measures tells us if an animal’s single phenotype is a good indicator of their breeding value?
Accuracy of Selection
Intensity of Selection
If 15% of the animals are selected, the intensity of selection is 1.55. What does 1.55 actually represent?
The mean of the selected animals is 1.55
The standard deviation of the selected animals is 1.55
The mean of the selected animals is 1.55 standard deviations away from the population mean
We are selecting 1.55% of the population
The Generation Interval is the:
The average age of potential parents when they are bred
The average age of parents when their offspring are selected
The average age of potential parents when they are selected
The average age of parents when their offspring are born
The change in the mean breeding value of a population over time is called a:
In a swine population, 210 litters are produced each generation. There are 7 pigs/litter than make it to selection age. Assuming 25 boars and 250 gilts are selected for growth rate each generation, what is the proportion of females selected?
In a swine population, 210 litters are produced each generation. There are 7 pigs/litter than make it to selection age. Assuming 25 boars and 250 gilts are selected for growth rate each generation, what is the proportion of males selected?
Given the following information. What is the generation interval for males in this population?
The following genetic parameters have been calculated for a population of Angora goats. If the σBV for 8-month weight is 4 lb., what is the genetic change expected in this population?
Which of the following pieces of information would NOT be included in genetic predictions?
Own performance record
Pedigree performance data
Progeny performance data
What is the name of the most widely used genetic prediction method?
Best Linear Unbiased Prediction
Large-scale genetic evaluation
The strength of the relationship between breeding values for two traits is called:
Breeding Value Covariance
Regression of Breeding Values
How close genes are on a chromosome
Mating of relatives
When a single gene affects more than one trait
When multiple genes affect a single trait
A phenotypic correlation between two traits is always:
The sum of the genetic and environmental correlations
The product of the genetic and environmental correlations
Greater than the genetic and environmental correlations
Between the genetic and environmental correlations
A genetic correlation of -0.25 indicates:
A weak negative relationship between breeding values for two traits
A moderate negative relationship between breeding values for two traits
A strong negative relationship between breeding values for two traits
A non-existent genetic relationship
The range for a genetic correlation is
0% to 100%
there is no range
Selection for one trait for a period of time followed by selection for a second trait for a period of time is called:
A(n) ________is a level of breeding value that is considered optimal.
Independent Culling Level
Which of the following is NOT a benefit using independent culling levels?
Save money by eliminating rejects earlier
Shortens the generation interval
Simultaneous selection for multiple traits
Convenience of selection at different stages in the animal’s life
Which of the following multiple-trait selection strategies is the fastest, most efficient way to improve multiple traits at the same time?
Economic Selection Index
A(n)________ is a value that represents an individual’s genetic merit across more than one trait.
Aggregate Breeding Value
Given the arrow diagram below, identify the common ancestor(s) of X and Y.
B, L, M,
A, B, C,
B, C, M
A, B, L, M
Given the arrow diagram below, identify the common ancestor(s) of the parents of X.
A, B, C
Genes that are copies of a single ancestral gene are said to be:
Identical By Decent
Identify which of the following notations correctly indicates the following:
37% of the individual X’s loci contain genes that are identical by descent
FX = 0.37
FX = 0.0037
RXY = 0.37
RXY = 1 - 0.37
The numerical relationship coefficient between half sibs of non-inbred parents is always:
True or False? In certain situations an animal can be considered its own common ancestor.
The population of animals whose parents are unknown or ignored in the pedigree are known as:
A sample population
A base population
Which method should you choose for calculating relationship and inbreeding coefficients in a pedigree of 103,970 individuals?
A mating system designed to maintain a substantial degree of relationship to a highly regarded ancestor or group is called:
A relationship matrix has been calculated for a small population and is given below. Calculate the relationship coefficient between X and C.
Which of the following is NOT a result of crossbreeding?
Masking of unfavorable alleles
More uniform animals
The average number born alive for Breed A is 8.4 piglets. The average number born alive for Breed B is 10.2 piglets. When these two breeds are crossed, the average number born alive is 10 piglets in the F1 generation. What is the amount of F1 hybrid vigor that is realized from this cross?
True or false: All traits contain direct, maternal, and paternal genetic components.
The maximum amount of hybrid vigor that is attainable is called:
Individual hybrid vigor
Retained hybrid vigor
Maternal hybrid vigor
F1 hybrid vigor
In a cross of C sires by C(AB) dams, what percentage of hybrid vigor will be retained after the F1 generation?
The mating of a hybrid to a purebred of a parent line or breed is known as:
At equilibrium, a three way spatial rotation will retain what percentage of F1 hybrid vigor?
A crossbreeding system in which maternal-breed females are mated to paternal breed sires is called a __________ crossbreeding system.
The Lacombe is a composite pig breed that is made up of 56% Landrace, 23% Berkshire, and 21% Chester White. Calculate the proportion of F1 hybrid vigor retained in advanced generations of this composite.
Which crossbreeding system combines a maternal rotation with terminal sires to produce market offspring?
Two way rotation
Three way spatial rotation
MOET has the potential to:
Increase the intensity of female selection lengthen the female generation interval
Increase the intensity of female selection and shorten the female generation interval
Increase the intensity of female selection and lengthen the male generation interval
Increase the intensity of female selection and shorten the male generation interval
Outside of ethical and theological issues, what is the biggest problem with cloning animals for food production?
Increases generation interval of our animal populations
Reduces our selection intensity
Diminishes genetic variance within a herd
Ruins the accuracy of EBV prediction
In the relationship matrix below, interpret what the bold value indicates:
The relationship between A and B is 0.5
The inbreeding coefficient of A is 0.5
The numerator of the relationship coefficient between A and B is 0.5
The numerator of the inbreeding coefficient is unknown
Which of the following biotechnologies improves the accuracy of male selection while simultaneously increase intensity at which males are selected?
Using sexed semen allows a producer to improve their selection intensity. Why?
More animals are being selected to be replacements of the next generation
More selection candidates are being produced
More genetic information is being provided
More variance is created
See Image for Question! :)
Direct selection for growth rate BV will result in a correlated genetic change of 0.10in/year in backfat
Backfat and growth rate have a weak, positive correlation
Direct selection for backfat BV will result in a correlated genetic change of 0.10in/year in growth rate
We expect a change of 0.10in/year change in backfat for every 1-lb/year change in growth rate
Multiple ovulation and embryo transfer can have positive effects on the genetic change within a herd. However if MOET is poorly managed it can result in:
Lengthening the generation interval
Reducing genetic variation
Negatively affecting accuracy of selection
Poor intensity of selection
The ability to measure genotype x environment interactions can be provided by:
Which of the following formulas should be used to estimate the amount of individual hybrid vigor that remains in the F3 generation when the amount of typical F1 hybrid vigor is known?
Any gene or DNA sequence used to identify location on a genetic map is called:
Polymerase Chain Reaction