Australian College of Veterinary Scientists
Membership examination
June/July 2008
Animal Breeding and Genetics
Paper 1
Perusal time: fifteen (15) minutes
Time allowed: two (2) hours after perusal
Answer four (4) from the six (6) questions only
All questions are of equal value
Subsections of questions are of equal value unless stated otherwise
Animal Breeding and Genetics Paper 1
Page 1 of 4
Paper 1: Animal breeding and genetics
Answer four (4) from the six (6) questions only.
1.
Briefly describe the meaning of each of the following terms:
–
karyotype
–
meiosis
–
heterozygous
–
locus
–
autosome
– epistasis.
2.
The polymerase chain reaction (PCR) is an in-vitro process that exploits certain
characteristics of deoxyribonucleic acid (DNA). Describe the PCR process and how it
can be used to detect the presence of particular sequences of DNA with great
sensitivity. In your answer, describe the characteristics of DNA that make this
reaction possible.
3.
‘The frequency of a particular allele in a population of offspring is expected to equal
the frequency of the same allele in the parent population, provided mating occurs at
random with respect to that locus, and there is no selection at that locus’. This
statement is an example of the Hardy-Weinberg law.
Discuss this principle in relation to the increase in frequency of anthelminticresistance alleles in successive generations of nematode parasites of domestic animals
when the host species is repeatedly and frequently treated with anthelmintic drugs. In
relation to the same principle, explain the circumstances under which rotation of
anthelmintics is expected to be useful in delaying the development of resistance.
Continued over page
Animal Breeding and Genetics Paper 1
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4.
Inbreeding occurs when two related individuals are mated. In most farm animal
breeding programs, some degree of inbreeding is common.
The risk of inbreeding and the degree of inbreeding within an animal population can
be estimated by calculating the effective population size (Ne), calculated as:
Ne = 4.s.d.L/(s+d)
where
s is the number of new sires entering the population per year
d is the number of new dams entering the population each year
L is the average age of the male and female parents when their offspring are born.
The increase in inbreeding per year in a population is approximately equal to
1/(2.Ne.L).
Consider a closed herd of cattle that consists of 1000 cows. No bulls are purchased
from outside the herd. In relation to the formulas given above, discuss the rate of
inbreeding in the herd and describe what factors might increase the rate significantly,
and what strategies might be used to minimise the rate of inbreeding. Include in your
answer the impact of the types of management strategies sometimes practised in
cattle-breeding programs, such as artificial insemination.
5.
The term ‘estimated breeding value’ (EBV) is frequently used in farm animal
breeding programs in Australia. EBVs are calculated for individual animals and
published to provide guidance to breeders and buyers of animals. EBVs are often
published with associated values for ‘accuracy’.
For example, one bull (Bull A) may be given an EBV for a trait of +5, with an
accuracy of 70%, while another bull (Bull B) may be given an EBV for the same trait
of +3, with an accuracy of 99%.
Describe what is meant by the terms EBV and accuracy, and illustrate your
understanding of these terms by discussing the relative merits of Bulls A and B.
Continued over page
Animal Breeding and Genetics Paper 1
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6.
The response to selection of a population of animals is proportional to the selection
intensity applied.
Using a breed or species of domestic animal with which you are familiar, briefly
describe a genetic selection program and discuss how the rate of genetic progress can
be slowed or accelerated by varying the selection intensity. Demonstrate in your
answer that you clearly understand all the following terms:
–
selection intensity
–
selection differential
–
heritability
–
genetic variance.
End of paper
Animal Breeding and Genetics Paper 1
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Australian College of Veterinary Scientists
Membership Examination
June/July 2008
Animal Breeding and Genetics
Paper 2
Perusal time: fifteen (15) minutes
Time allowed: two (2) hours after perusal
Answer all four (4) questions
All questions are of equal value
Subsections of questions are of equal value unless stated otherwise
Animal Breeding and Genetics Paper 2
Page 1 of 2
Paper 2: Animal breeding and genetics
Answer all four (4) questions.
1.
Select an animal industry of your choice and describe how crossbreeding is used, or
could be used, to increase the productivity of the farmed animals in that industry.
Include in your answer an explanation of why the strategy is or could be successful.
2.
The mathematical technique of best linear unbiased prediction (BLUP) is now used
widely in the animal industries of Australia and other developed countries to provide
genetic evaluation of animals and to estimate rates of genetic change in those
populations.
Select one (1) industry that has a genetic evaluation program based on BLUP
technology, and describe the processes involved in producing information for
breeders, starting with the mechanisms for data collection from breeders. It is not
necessary to describe what BLUP is, but you must describe in general terms what it
does. Your answer should also address the mechanisms involved in the flow of ‘raw’
information from breeders to a central processing bureau and as ‘processed’
information back to the users of the information.
3.
Using as an example an industry of your choice, describe how modern molecular
genetic techniques are being used to identify individuals with particular beneficial or
deleterious traits.
4.
In early 2008, the United States Food and Drug Administration (FDA) declared there
is no reason that cloned livestock and their offspring cannot be used for food. The
ruling came despite opposition from some consumer groups.
Give your views about this decision by the FDA and, using your understanding of the
science of genetics, argue whether you believe this decision to be correct or incorrect.
End of paper
Animal Breeding and Genetics Paper 2
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