Genetics Flashcards
Impaired expression of adhesion molecules can be lethal. In Holstein cattle, a hereditary syndrome has been identified and is the product of:
a. A mutation in CD18 resulting in minimal expression of β2 integrins that lead to severe chronic infections
b. A mutation of ICAM-1 in the endothelium
c. A mutation of PECAM-1 in the interendothelial junctions
d. None of the above
a. A mutation in CD18 resulting in minimal expression of β2 integrins that lead to severe chronic infections
Is an autosomal recesive disorder, clinically characterized by chronic bacerial infections and premature deth. In calves affected, leukocytes lack of glycoproteins.
A sheep rancher presents a 3-year old Suffolk ram with a history of severe weight loss, wool loss and pruritus. You recommend genetic testing culling all animals with genotype:
a. AA
b. QQ
c. RR
d. QR
b. QQ
Cow with oculocutaneous albinism, photophobia, tendency to bleed, increased susceptibility to infection and enlarged granules in neutrophilic and eosinophilic polymorphonuclear leukocytes.
Chediak-Higashi syndrome
Autosomal recessive disorder caused by mutations in the lysosomal trafficking regulator (LYST) gene
A newborn Belgian foal presents with multiple areas of ulceration around the coronary band and oral cavity.
Which of the following BEST describes the underlying defect?
a) A defect in the Keratin-5 gene
b) A defect in the Laminin-5 gene
c) Deficient expression of epidermal integrin
d) A mutation in the PMEL17 gene
b) A defect in the Laminin-5 gene
Equine epitheliogenesis imperfecta (EI). Histopathology reveals separation of the epidermis from the dermis. EI-affected foals showed abnormal hemidesmosomes, which lacked a subbasal plate.
Severe combined immunodeficiency in the Arabian foal is due to which of the following?
a) A mutation in the sodium/myo-inositol co-transporter gene (SLC5A3) resulting in an abnormal response to osmotic stress in lymphoid tissues.
b) A mutation in the btk gene on the X chromosome resulting in defects in B cell proliferation.
c) A mutation in the DNA-PK gene resulting in a lack of V(D)J recombination.
d) A mutation in the PAX5 genes resulting in reduced expression of CD19.
c) A mutation in the DNA-PK gene resulting in a lack of V(D)J recombination.
A disease with an autosomal recessive mode of inheritance will result in which of the following scenarios?
a) Breeding a carrier to a carrier will result in a carrier 100% of the time.
b) Breeding a carrier to a carrier will result in an affected animal 25% of the time.
c) Breeding a non-carrier to a carrier will result in an affected animal 50% of the time.
d) Breeding a non-carrier to a carrier will result in a carrier 75% of the time.
b) Breeding a carrier to a carrier will result in an affected animal 25% of the time.
What is the gene mutation causant of HERDA??
Hyperelastosis cutis or Hereditary Equine Regional Dermal Asthenia is caused by a mutation in the procollagen I N-proteinase gene. Commonly affecting horses.
What is the metabolic defect causative of congenital erythropoietic porphyria?
It is a hereditary deficiency of the enzyme uroporphyrinogen III synthase (UROS), which catalizes an essential step in the synthesis of the porphyrin structure of hemoglobin.
What will be the likely origin for this skin lesion in this 4 month-old Fleckvieh calf?
a. Chediak-Higashi Syndrome
b. Lethal trait A46
c. Selective IgG2 Deficiency
d. Hypothrichosis
b. Lethal trait A46
What is the mutation for the lethal trait A46 in a calf?
a. Mutation in a phospholipase D4 encoding gene (PLD4)
b. Mutation in the SLC39A4 gene
c. Mutation in the SLC5A3 gene
d. Mutation in the gene encoding the catalytic subunit of DNA-dependent protein kinase (DNA-PK)
a. Mutation in a phospholipase D4 encoding gene (PLD4)
Which of the following findings are associated with cholesterol deficiency, a recently recognized autosomal recessive genetic defect, in Holstein cattle?
a. Chronic diarrhea and low blood triglycerides
b. Failure to thrive and high blood triglycerides
c. Chronic diarrhea and anorexia
d. Failure to thrive and fatty liver
a. Chronic diarrhea and low blood triglycerides
A 10 year old TB gelding presents for evaluation of recurrent sinus infections. Blood work reveals a severe, prolonged lymphopenia. Radial immunodiffusion shows absent IgM, low IgG and a normal IgA concentration. Lymphocyte phenotyping shows a deficiency in CD19-like cells.
What is the most likely diagnosis?
a. Lymphosarcoma
b. Common variable immunodeficiency
c. X-linked agammaglobulinemia
d. Selective IgM deficiency
b. Common variable immunodeficiency
Which of the following mating combination will lead to ileocolonic agangliosis in the offspring?
a. Overo stallion with overo mare
b. Tobiano mare with overo stallion
c. Tobiano stallion with overo mare
d. Appaloosa stallion with overo mare
a. Overo stallion with overo mare
