15: Genetic resemblance pt3

Question 1

Equation for coefficient of inbreeding

Answer 1

F(x)= slide 4

Question 2

How to determine the coefficient of inbreeding

Answer 2

Identify common ancestors and unique paths through to animal of interest
Compute f(x) for each path, add them

Question 3

What is relationship

Answer 3

Probability that a randomly taken allele from individual is identical by descent (IBD) to a randomly taken allele from individual Y

Question 4

What is Wright’s Coefficient of Relationship

Answer 4

Rxy
Probable proportion of one individual’s genes (X) that are identical by descent to genes of a second individual (Y)

Correlation between breeding values of two individuals due to pedigree relationship alone

Question 5

Rxy ranges from…

Answer 5

0 (unrelated) to 1 (identical twins)

Question 6

Equation for Rxy

Answer 6

slide 10

Question 7

Rxy for identical twins? Full siblings? Dam?

Answer 7

100
50
50

Question 8

Fx vs Rxy

Answer 8

Fx: Probability that both alleles of a pair in an individual are identical by descent

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

Question 9

The closer the pedigree relationship between the parents, the…

Answer 9

higher the inbreeding in their progeny

Question 10

What is the additive genetic relationship

Answer 10

a(xy)
Measure of the proportion of the genome shared by X and Y

Question 11

Relationship between coefficient of inbreeding and additive genetic relationship

Answer 11

Fx = half the parent’s a(xy)

Question 12

Three methods for calculating inbreeding and relationships coefficients in a population

Answer 12

1) The Path Method
2) The Tabular Method
3) Genomic Matrix based on DNA markers

Question 13

What does the choice for method of calculating inbreeding/relationship coeff in a population depend on

Answer 13

• number of coefficients to be determined
• size and complexity of the pedigree
• availability of computer hardware and software

Question 14

Steps for the path method

Answer 14

1. Convert pedigree into arrow diagram
2. Locate common ancestors (inbreeding=CA of dam and sire, relationship=CA to two individuals of interest)
3. Calculate inbreeding coefficient of CA’s
4. Fill in table
5. Sum the last column of the tab le to compute Fx
6. For Rsd, divide sum of step 5 by denominator

Question 15

Rules of the path method

Answer 15

1. Each pair of paths must start from CA and follow direction of the arrows in the diagram (no backtracking)
2. Pair of paths must not include the same individual (except CA)
3. Animal might be considered its own common ancestor

Question 16

Slide 26-41

Answer 16

EXAMPLE CALCULATIONS!! LOOOOK