AB&G - 2015 end of year exam

Question 1

Calculate the annual response to selection in performance when selecting directly on the trait

Answer 1

R=(variationselection intensityaccuracy)/generation interval

Question 2

If your selection was based on genetic markers that accounted for just 20% of the genetic variance, then what is the annual response to selection?

Answer 2

CORRELATED RESPONSE (?)
CR=genetic correlation * selection intensity * heritability of trait 1 * heritability of trait 2 * phenotypic variation (SD) in trait 2 / generation interval

Question 3

Comment on how the response to selection using markers compared to selection on the traits and why it could be useful even when accounting for such a low proportion (20%) of genetic variation.

Answer 3

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Question 4

Describe what each component of these two equations listed below are. Explain (in laymen’s terms) why the variance in a trait due to a major gene affecting the trait is a function of the frequency of that gene (technically, the allele frequency).

= a + d (q p)
2/A = 2pq

Answer 4

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Question 5

What is the difference between heritability and heterosis? State what components of genetic variance each are affected by. Also give example of traits which are easier to improve by crossbreeding than selection.

Answer 5

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Question 6

Describe how a 3 breed rotational cross would work using a diagram and the 3 potential breed proportions once the cross is at a stable level (i.e. after 7 generations)?

Answer 6

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Question 7

ANIMAL GENETIC RESOURCES

Name the 5 (“The big five”) most important species in global animal production and give their chromosome (2n) numbers.

Answer 7

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Question 8

ANIMAL GENETIC RESOURCES

Describe the desired genetic structure of small populations (5 features).

Answer 8

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Question 9

ANIMAL GENETIC RESOURCES

List the 4 objectives of the global strategy for Domestic Animal Diversity (DAD).

Answer 9

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Question 10

ANIMAL GENETIC RESOURCES

Describe the “Weitzman approach” to conservation of genetic resources (3 major points).

Answer 10

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Question 11

NON-MENDELIAN INHERITANCE

What is the major difference between the two major types of non-Mendelian inheritance discussed in the lecture?

Answer 11

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Question 12

NON-MENDELIAN INHERITANCE

When and where do major waves of epigenetic reprogramming occur?

Answer 12

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Question 13

NON-MENDELIAN INHERITANCE

Define genomic imprinting.

Answer 13

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Question 14

NON-MENDELIAN INHERITANCE

Name 4 major functions of epigenetic modifications in the genome.

Answer 14

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Question 15

NON-MENDELIAN INHERITANCE
Contrast and explain standard features and properties of the genome and epigenome (4 features/properties). What is the most important difference?

Answer 15

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Question 16

MOLECULAR GENETICS

Define what is meant by a “major” gene.

Answer 16

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Question 17

MOLECULAR GENETICS

What is the genetic term used to describe the other genes controlling the speed and extent of wool shedding?

Answer 17

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Question 18

MOLECULAR GENETICS

Define what is meant by incomplete penetrance.

Answer 18

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Question 19

MOLECULAR GENETICS

Provide a possible explanation for the incomplete penetrance of a major gene.

Answer 19

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Question 20

MOLECULAR GENETICS

What is a “virtual” genome? Describe how it is generated.

Answer 20

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Question 21

MOLECULAR GENETICS

Explain how a “virtual” genome can be useful.

Answer 21

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Question 22

MOLECULAR GENETICS

Describe how you could identify the major gene for wool shedding.

Answer 22

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Question 23

MOLECULAR GENETICS
Why is it better to identify and select the causative variant in a gene rather than use markers for selection? In your explanation, be sure to define a “causative variant” and “marker”, and describe 2 reasons why GAS is better than MAS.

Answer 23

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Question 24

MOLECULAR GENETICS
Given that the major gene is autosomal dominant, is it worth identifying the major gene for a breeding program in a shedding breed such as Dorper? Why or why not?

Answer 24

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Question 25

MOLECULAR GENETICS
Given that the major gene is incompletely penetrant, is it worth identifying the major gene for a breeding program in a shedding breed such as Dorper? Why or why not?

Answer 25

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Question 26

MOLECULAR GENETICS
If the gene was identified, how could you introgress the major gene for shedding into a non-shedding breed such as Suffolk or Texel?

Answer 26

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Question 27

MOLECULAR GENETICS
Using the information above and your answers, describe a complete breeding program for shedding in Suffolks or Texels. Be sure to consider EACH of the dot points above.

Answer 27

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Question 28

MOLECULAR GENETICS
What are 2 reproductive technologies that could be used to improve your breeding program? Be sure to explain HOW these technologies would improve your breeding program.

Answer 28

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