Breeding Terms Exam 3

Single Trait Selection

Selection for one trait

Multiple Trait Selection

Selection for more than one trait

Aggregate Breeding Value

The breeding value of an individual for a combination of traits

Tandem Selection (Serial Selection)

Selection for one trait, then another

Independent Culling Levels

Minimum standards for traits undergoing multiple-trait selection

Economic Selection Index

An index, or combination of weighting factors, and genetic information - either phenotypic data or genetic predictions - on more than one trait. These values are used in multiple-trait selection to predict aggregate breeding value

Breeding Objective

A weighted combination of traits defining aggregate breeding value for use in an economic selection index

Economic Weight

The change in aggregate breeding value (the change in profit if that is how aggregate breeding value is measured) due to an independent, one unit increase in performance in a trait

Inbreeding

The mating of relatives or, more specifically, the mating of individuals more closely related than average for the population

Common Ancestor

An ancestor common to more than one individual. In the context of inbreeding, the term refers to an ancestor common to the parents of an inbred individual

Identical by Descent

Two genes are identical by descent if they are copies of a single ancestral gene

Hybrid Vigor (Heterosis)

An increase in the performance of hybrids over that of purebreds, most noticeably in traits like fertility and survivability

Inbreeding Coefficient

A measure of the level of inbreeding in an individual

Inbreeding Coefficient

The probable proportion of an individual’s loci containing genes that are identical by descent

Inbreeding Coefficient

The probability that both genes of a pair in an individual are identical by descent

Inbreeding Depression

The reverse of hybrid vigor - a decrease in the performance of inbreds most noticeably in traits like fertility and survivability

Wright’s Coefficient of Relationship

A measure of pedigree relationship

Wright’s Coefficient of Relationship

The correlation between the breeding values of two individuals due to pedigree relationship alone

Wright’s Coefficient of Relationship

The probable proportion of one individual’s genes that are identical by descent to genes of a second individual

Prepotency

The ability of an individual to produce progeny whose performance is especially like its own and(or) is especially uniform

Alike in State

Genes that are alike in state function the same and have exactly the same chemical structure