ANSC 4395 Breeding & Genetics - Test 3
Solved 100% Correct 2024
2 statistics useful for determining if a relationship exists - ANSWER-Correlation and
Regression
An individual that is Aa will produce gametes - ANSWER-- Half will contain A, other half
will contain a
- When populations are small, there may not be exactly half of each
bell curve (normal distribution) - ANSWER-A statistical distribution that phenotypes will
closely approximate
- Allows us to use statistics to describe populations and their genetic makeup
bYX - ANSWER-read as the regression of Y on X
Calculating the regression coefficient - ANSWER-- The numerator is the same as the
numerator in the correlation coefficient
- The denominator is the same as the numerator of the variance of X
- Does make a difference which variable is X and which is Y
coefficient of variation - ANSWER-Standard deviation as percentage of the mean
- Useful for comparing the relative amounts of variation for various traits
Common characteristics of Polygenic and Simply Inherited - ANSWER-1. Both are
subject to the same Mendelian Mechanisms: Law of Segregation and Independent
Assortment
2. Affected by dominance and epistasis
3. Principles of selection and mating apply to both
- Attempt to increase frequency of desirable alleles
(More difficult to do with polygenic traits)
Continuous Variable - ANSWER-for any 2 values, there is a possible intermediate value
EX. weaning weight and yearling weight
Correlation - ANSWER-Calculation of the correlation coefficient
Correlation coefficient - ANSWER-The measure of the association between two
variables (r XY)
discrete variable - ANSWER-has distinct classes (whole number)
EX. 3 of lambs born
Equation of a straight line:
, Y = a + bX - ANSWER-Y = dependent or predicted variable
X = independent or predictor value
b = slope of the line or regression coefficient
a = the intercept, or the value of Y when X = 0
Examples of Polygenic Traits - ANSWER-Weaning weights, milk yield, REA... CANT
DO TEST MATINGS FOR THIS TYPE OF TRAIT
Examples of Simply-Inherited Traits - ANSWER-Coat color, horns
Function of the Number of genes involved - ANSWER-- The more genes involved, the
more DIFFICULT it is to observe the effects of individual genes, and therefore the less
specific info we have about those genes
- When a few or one gene affects a trait, the effects of those genes are well understood
(Exact genotype may not be known, but a probable genotype may be identified.)
If heterozygous females are hard to find, then mate sire to daughters - ANSWER--
Assume the daughter's dams do not carry the recessive gene
- Probability that a daughter carries the recessive gene is 1/2 if sire is heterozygous
If the condition is deleterious - ANSWER-- May be hard to find homozygous recessive
- Use known heterozygotes
- Probability of a recessive offspring is 1/4 or the probability of the offspring showing the
dominant phenotype is 3/4
Mean (average) - ANSWER-main measure of central tendency
Measures of variability - ANSWER-Standard deviation
Variance
Coefficient of variation
Median - ANSWER-- Other measure of central tendency
- Value with the same number of observations with larger values as the number of
observations with smaller values
- Number in the middle
Method with the highest probability of detection - ANSWER-Mating to recessive
- Probability of siring a recessive offspring is 1/2
Mode - ANSWER-- Other measure of central tendency
-Most frequent value
Most economically important traits are - ANSWER-quantitative
Niche markets - ANSWER-markets more sensitive to simply-inherited traits
Solved 100% Correct 2024
2 statistics useful for determining if a relationship exists - ANSWER-Correlation and
Regression
An individual that is Aa will produce gametes - ANSWER-- Half will contain A, other half
will contain a
- When populations are small, there may not be exactly half of each
bell curve (normal distribution) - ANSWER-A statistical distribution that phenotypes will
closely approximate
- Allows us to use statistics to describe populations and their genetic makeup
bYX - ANSWER-read as the regression of Y on X
Calculating the regression coefficient - ANSWER-- The numerator is the same as the
numerator in the correlation coefficient
- The denominator is the same as the numerator of the variance of X
- Does make a difference which variable is X and which is Y
coefficient of variation - ANSWER-Standard deviation as percentage of the mean
- Useful for comparing the relative amounts of variation for various traits
Common characteristics of Polygenic and Simply Inherited - ANSWER-1. Both are
subject to the same Mendelian Mechanisms: Law of Segregation and Independent
Assortment
2. Affected by dominance and epistasis
3. Principles of selection and mating apply to both
- Attempt to increase frequency of desirable alleles
(More difficult to do with polygenic traits)
Continuous Variable - ANSWER-for any 2 values, there is a possible intermediate value
EX. weaning weight and yearling weight
Correlation - ANSWER-Calculation of the correlation coefficient
Correlation coefficient - ANSWER-The measure of the association between two
variables (r XY)
discrete variable - ANSWER-has distinct classes (whole number)
EX. 3 of lambs born
Equation of a straight line:
, Y = a + bX - ANSWER-Y = dependent or predicted variable
X = independent or predictor value
b = slope of the line or regression coefficient
a = the intercept, or the value of Y when X = 0
Examples of Polygenic Traits - ANSWER-Weaning weights, milk yield, REA... CANT
DO TEST MATINGS FOR THIS TYPE OF TRAIT
Examples of Simply-Inherited Traits - ANSWER-Coat color, horns
Function of the Number of genes involved - ANSWER-- The more genes involved, the
more DIFFICULT it is to observe the effects of individual genes, and therefore the less
specific info we have about those genes
- When a few or one gene affects a trait, the effects of those genes are well understood
(Exact genotype may not be known, but a probable genotype may be identified.)
If heterozygous females are hard to find, then mate sire to daughters - ANSWER--
Assume the daughter's dams do not carry the recessive gene
- Probability that a daughter carries the recessive gene is 1/2 if sire is heterozygous
If the condition is deleterious - ANSWER-- May be hard to find homozygous recessive
- Use known heterozygotes
- Probability of a recessive offspring is 1/4 or the probability of the offspring showing the
dominant phenotype is 3/4
Mean (average) - ANSWER-main measure of central tendency
Measures of variability - ANSWER-Standard deviation
Variance
Coefficient of variation
Median - ANSWER-- Other measure of central tendency
- Value with the same number of observations with larger values as the number of
observations with smaller values
- Number in the middle
Method with the highest probability of detection - ANSWER-Mating to recessive
- Probability of siring a recessive offspring is 1/2
Mode - ANSWER-- Other measure of central tendency
-Most frequent value
Most economically important traits are - ANSWER-quantitative
Niche markets - ANSWER-markets more sensitive to simply-inherited traits
