Question 1

Which of the following best describes what Embark genetic testing analyzes in dogs?

Accepted Answer

Single Nucleotide Polymorphisms (SNPs) and unique alleles of genes

Question 2

A dog has the genotype GG at a locus associated with tail length in Australian Shepherds. What is the expected phenotype?

Accepted Answer

Normal length tail

Question 3

Which of the following is a real-world application of SNP analysis in veterinary genetics?

Accepted Answer

Identifying genetic predispositions to diseases such as Degenerative Myelopathy

Question 4

The Illumina genotyping chip used in Embark testing works by:

Accepted Answer

Using single-stranded DNA oligos attached to beads on a microarray to detect specific SNPs via fluorescent labeling

Question 5

A dog is found to be homozygous for the AA genotype at the SOD1 gene associated with Degenerative Myelopathy (DM). Which statement is most accurate?

Accepted Answer

The dog is predisposed to DM, but incomplete penetrance means it may not develop the disease

Question 6

Which of the following best explains the concept of incomplete penetrance as it relates to Degenerative Myelopathy in dogs?

Accepted Answer

Some dogs with the risk genotype may not develop the disease due to genetic and environmental factors

Question 7

A mutation in the SOD1 gene leads to a substitution of glutamic acid (E) with lysine (K) at position 40 (E40K). What is the most likely molecular consequence?

Accepted Answer

Disruption of a salt bridge, destabilizing the protein structure

Question 8

Which of the following is a potential benefit of genetic testing for dog breeders?

Accepted Answer

Identifying dogs with heterozygous genotypes for breed-specific, recessive diseases to avoid pairing them

Question 9

Which of the following best describes the inheritance pattern of Degenerative Myelopathy (DM) in dogs?

Accepted Answer

Autosomal recessive with incomplete penetrance

Question 10

A dog with the genotype GA at the SOD1 locus is considered a:

Accepted Answer

Carrier (at risk of passing the allele but not typically affected)

Question 11

Which of the following best explains why some Dalmatians produce too much uric acid?

Accepted Answer

A mutation in a gene involved in uric acid metabolism

Question 12

If a genetic test identifies a dog as homozygous for a lethal allele associated with tail length, what is the expected outcome?

Accepted Answer

The genotype is not observed because it is lethal

Question 13

Which of the following is a limitation of genetic testing in dogs?

Accepted Answer

It may reveal unexpected information that could be stressful for owners

Question 14

A dog receives a gene therapy injection targeting SOD1 RNA in its cerebrospinal fluid. What is the intended effect of this treatment?

Accepted Answer

To silence mutant SOD1 RNA and slow the progression of Degenerative Myelopathy

Question 15

Which of the following best describes the function of the SOD1 protein?

Accepted Answer

A detoxifying enzyme that maintains redox homeostasis in multiple cellular compartments

Question 16

A breeder wants to avoid producing puppies with a recessive disease. If both parents are carriers (heterozygous), what is the probability that a puppy will be affected? Use the formula for Mendelian inheritance: $$P = p^2$, where p$ is the frequency of the recessive allele in the cross.

Accepted Answer

$$P = 0.25$$

Question 17

Which of the following is a plausible reason why a genetic test might not predict disease development with certainty?

Accepted Answer

Environmental and other genetic factors can influence whether a predisposed individual develops the disease

Question 18

Which of the following best describes a 'gain of function' mutation as it relates to SOD1 and Degenerative Myelopathy?

Accepted Answer

A mutation that results in the protein acquiring a new, often toxic, activity

Question 19

Which of the following is a real-world ethical consideration associated with genetic testing in dogs?

Accepted Answer

Genetic information may lead to lifestyle changes for pets that could be stressful

Genetic Testing in Dogs: Principles, Methods, and Applications

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