Relationship and Pedigree

Question 1

What does it mean when animals are related?

Answer 1

Related animals have genes in common.

Question 2

What are the two reasons why it’s important to know the relationship between animals?

Answer 2

1) To estimate the performance value of an untested animal

2) To control inbreeding

Question 3

Define pedigree.

Answer 3

The set of known parent-offspring relationships in a population, often displayed as a family tree diagram.

Question 4

Define additive relationship.

Answer 4

An estimate of the fraction of alleles that two individuals share because they have one or more common ancestor(s).

Question 5

Define relationship coefficient.

Answer 5

The measure of relationship that ranges from 0 to 1. It is equivalent to the correlation between BV.

Question 6

What would be the additive relationship between half sibs?

Answer 6

1/4

Question 7

What would be the additive relationship between full sibs?

Answer 7

1/2

Question 8

Define Identity by Descent (IBD)

Answer 8

Genes/alleles are exact replicates from a common ancestor.

Question 9

Define Identity by State (IBS).

Answer 9

Genes/alleles are functionally/structurally identical but matches by coincidence.

Question 10

Define inbreeding coefficient.

Answer 10

The probability that both genes at a locus are identical by descent.

Question 11

What are the four ways to represent an animal’s lineage?

Answer 11

• bracket
• path
• genogram
• table