ANSC 4395 FINAL EXAM QUESTONS WITH
COMPLETE ANSWERS
Selection - -The practice of allowing certain individuals more opportunity to
reproduce than others.
Only means of making genetic improvement in a closed population.
Improvement made by increasing the frequency of desired genes.
Results of selection are predictable in magnitude and direction.
-Response to selection - -Progress resulting from selection is called
response.
Genetic change that occurs as a result of selection.
Ex. If environmental conditions have remained constant, the phenotypic
change should mirror the genetic change.
-selection differential - -the difference between the mean performance of
the selected individuals and the average of the entire herd.
-Generation Interval - -The length of time it takes to replace the members of
on generation in a herd.
Symbolized by: L
-Breeding Value - -An individual's phenotype is the result of its genetic
merit and the effect of the environment.
-Estimated Breeding Value (EBV) - -Actual breeding value of an individual is
never known.
Can be estimated from an individual's performance and the performance of
its relatives.
Addition of information from relatives will always increase confidence in an
estimate of breeding value.
-Individual's own performance - -Single most important price of into for
estimating breeding value.
Accuracy can be increased by measuring progeny or sibs.
Measuring relatives cannot take the place of measuring the individual itself
until numerous records on relatives have been obtained.
-Multiple records on an individual - -Some traits measured several times
during and animal's lifetime.
Ex. egg production, milk production, litter size, litter weight.
IF a trait is measured several times, each value should be used in an
estimate of breeding value.
-Sib information - -Almost any animal will have siblings.
COMPLETE ANSWERS
Selection - -The practice of allowing certain individuals more opportunity to
reproduce than others.
Only means of making genetic improvement in a closed population.
Improvement made by increasing the frequency of desired genes.
Results of selection are predictable in magnitude and direction.
-Response to selection - -Progress resulting from selection is called
response.
Genetic change that occurs as a result of selection.
Ex. If environmental conditions have remained constant, the phenotypic
change should mirror the genetic change.
-selection differential - -the difference between the mean performance of
the selected individuals and the average of the entire herd.
-Generation Interval - -The length of time it takes to replace the members of
on generation in a herd.
Symbolized by: L
-Breeding Value - -An individual's phenotype is the result of its genetic
merit and the effect of the environment.
-Estimated Breeding Value (EBV) - -Actual breeding value of an individual is
never known.
Can be estimated from an individual's performance and the performance of
its relatives.
Addition of information from relatives will always increase confidence in an
estimate of breeding value.
-Individual's own performance - -Single most important price of into for
estimating breeding value.
Accuracy can be increased by measuring progeny or sibs.
Measuring relatives cannot take the place of measuring the individual itself
until numerous records on relatives have been obtained.
-Multiple records on an individual - -Some traits measured several times
during and animal's lifetime.
Ex. egg production, milk production, litter size, litter weight.
IF a trait is measured several times, each value should be used in an
estimate of breeding value.
-Sib information - -Almost any animal will have siblings.
