ICAR AIEEA (PG): Master's entrance, Veterinary Science and Animal Sciences · India · NTA for ICAR
Original practice questions written to the published syllabus · not past papersMolecular tools used in diagnosis, vaccines and reproduction: recombinant DNA, PCR, cell culture, monoclonal antibodies, cloning, transgenics and genomics, with their biosafety rules.
In the exams: ICAR AICE-JRF core group 08; ICAR AIEEA-PG 12 (Animal Biotechnology)
ICAR AIEEA (PG), Code 12 Animal Biotechnology
Principles and landmark facts: restriction enzymes and vectors, PCR steps and variants, qPCR Ct and efficiency, HAT selection, cell lines, iPSC factors, Dolly, CRISPR mechanism, sexed semen principle, DIVA vaccines, and the Indian biosafety committees (IBSC, RCGM, GEAC).
How our questions for ICAR AIEEA spread across the units of Veterinary and Animal Biotechnology. Difficulty: 22 easy, 36 medium, 4 hard.
| Molecular biology and recombinant DNA | 7 | |
| Embryo transfer and in-vitro fertilisation | 7 | |
| Genomics and bioinformatics | 7 | |
| PCR and quantitative PCR | 6 | |
| Molecular diagnostics | 5 | |
| Animal tissue culture | 5 | |
| Sub-unit and recombinant vaccines | 5 | |
| Hybridoma technology and monoclonal antibodies | 4 | |
| Stem cells | 4 | |
| Cloning | 4 | |
| Transgenic animals | 4 | |
| Biosafety and regulation | 4 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Bovine leukocyte adhesion deficiency (BLAD) in Holstein cattle is caused by a mutation in the gene for:
B. The integrin beta-2 subunit (CD18)
BLAD is an autosomal recessive defect in CD18 (ITGB2), so neutrophils cannot adhere and migrate, and calves have recurrent infections. Uridine monophosphate synthase is DUMPS, the ryanodine receptor is porcine stress syndrome, myostatin is double muscling.
Which cell line derived from African green monkey kidney is widely used for virus isolation?
C. Vero
Vero cells come from African green monkey kidney. MDBK is Madin-Darby bovine kidney, BHK-21 baby hamster kidney and CRFK Crandell-Rees feline kidney.
Further reading: Freshney RI. Culture of Animal Cells: A Manual of Basic Technique and Specialized Applications, 7th ed.
In hybridoma production, the myeloma fusion partner is chosen to lack which enzyme so that unfused myeloma cells die in HAT medium?
D. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
Aminopterin in HAT blocks dihydrofolate reductase and thus de novo nucleotide synthesis. Cells must use the salvage pathway, which needs HGPRT. HGPRT-negative myeloma cells die; hybrids gain HGPRT from the spleen B cell. Dihydrofolate reductase is the enzyme aminopterin blocks, not the one missing from the myeloma.
Further reading: Kohler G, Milstein C. Nature 1975;256:495-497.
Unfused spleen B cells do not survive long after a hybridoma fusion because:
B. Normal B cells have a limited lifespan in culture
Primary B cells have HGPRT, so HAT does not kill them, but they cannot divide indefinitely and die within days. Only fused hybrids combine immortality with HGPRT.
After hybridoma fusion, antibody-positive wells are subcloned by limiting dilution. The purpose is to:
D. Ensure the culture derives from a single cell so the antibody is truly monoclonal
An early positive well may contain several hybrid clones. Plating at about one cell per well or less and re-screening ensures a single clone. Class switching does not happen in culture this way.
A country vaccinates pigs against Aujeszky's disease with a glycoprotein E (gE)-deleted vaccine. How can infected herds be identified?
B. By testing for antibodies to gE, which vaccinated but uninfected pigs lack
This is the classic DIVA (differentiating infected from vaccinated animals) system: field virus induces anti-gE antibodies, the deleted vaccine does not. Glycoprotein B is present in both vaccine and field virus, so antibodies to it cannot distinguish them.
Further reading: Tizard IR. Veterinary Immunology, 10th ed.; Tizard IR. Vaccines for Veterinarians, 2021.
Embryonic stem cells are derived from which part of the blastocyst?
A. Inner cell mass
The inner cell mass gives rise to the embryo proper and yields pluripotent ES cells. Trophectoderm forms the placenta; the zona is an acellular glycoprotein coat.
Dolly the sheep was produced by somatic cell nuclear transfer using a nucleus from which cell type?
C. A mammary gland cell of an adult ewe
Dolly (Roslin Institute, born 1996) came from a mammary epithelial cell of a six-year-old Finn Dorset ewe placed in an enucleated oocyte from a Scottish Blackface ewe. Fetal fibroblasts and embryonic cells were also used as donors in the same study, but Dolly was the adult-cell clone.
Further reading: Wilmut I et al. Nature 1997;385:810-813.
Genomic selection, as proposed by Meuwissen, Hayes and Goddard in 2001, predicts breeding values from:
C. Dense genome-wide marker effects estimated in a reference population
Genomic selection sums the estimated effects of thousands of genome-wide SNPs, capturing many small-effect loci. Using one linked marker is marker-assisted selection; pedigree-only and progeny-test methods are the traditional approaches.
Further reading: Meuwissen THE, Hayes BJ, Goddard ME. Genetics 2001;157:1819-1829.
In the 3Rs principle of Russell and Burch, replacing an animal potency test for a vaccine with a validated cell-culture or serological assay is an example of:
A. Replacement
Replacement avoids or replaces animal use; reduction uses fewer animals for the same information; refinement lessens pain and distress. Rehabilitation is not one of the 3Rs.
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