AB&G - 2015 end of year exam Flashcards Preview

III - AB&G (Animal Breeding & Genetics) > AB&G - 2015 end of year exam > Flashcards

Flashcards in AB&G - 2015 end of year exam Deck (28)
1

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

R=(variation*selection intensity*accuracy)/generation interval

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?

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

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

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

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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.

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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)?

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7

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

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8

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

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9

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

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10

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

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11

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

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12

NON-MENDELIAN INHERITANCE
When and where do major waves of epigenetic reprogramming occur?

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13

NON-MENDELIAN INHERITANCE
Define genomic imprinting.

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14

NON-MENDELIAN INHERITANCE
Name 4 major functions of epigenetic modifications in the genome.

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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?

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16

MOLECULAR GENETICS
Define what is meant by a “major” gene.

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17

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

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18

MOLECULAR GENETICS
Define what is meant by incomplete penetrance.

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19

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

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20

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

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21

MOLECULAR GENETICS
Explain how a “virtual” genome can be useful.

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22

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

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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.

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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?

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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?

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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?

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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.

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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.

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