Previous Year Questions
2024
ZOOLOGY — HONOURS
Paper : DSCC-3
(Genetics)
Full Marks : 75
Answer question nos. 1 and 2, and any four questions from the rest.
Section - A
1. Answer any ten questions :
2 × 10
(a) Distinguish between paracentric and pericentric inversion.
(b) Define Interference and coincidence.
(c) Define lethal alleles with example.
(d) What is pleiotropy?
(e) What is non-allelic interaction?
(f) What is Robertsonian translocation?
(g) Distinguish between complementation and recombination.
(h) What are pseudoalleles? Give example.
(i) What is the probable effects of frameshift mutation?
(j) Define complex traits with example.
(k) What is Bombay Phenotype?
(l) Why can Ds elements not move themselves?
(m) What is Philadelphia Chromosome?
(n) Distinguish between epistatic and hypostatic gene.
(o) Define autoploidy and alloploidy.
Section - B
2. Write short notes on (any three) :
5 × 3
(a) Incomplete linkage and its demonstration
(b) Shell Spiraling in Snail
(c) Nucleosome model
(d) Human Karyotyping
(e) LINE and SINE elements in human.
Section - C
3. (a) With structure, explain the molecular basis of mutations induced by UV light.
(b) Write down the salient features of kappa particles in Paramoecium sp.
(c) Explain the transmission of kappa particles during short duration and long duration conjugation in Paramoecium sp. with suitable diagrams. 4+2+4
(b) Write down the salient features of kappa particles in Paramoecium sp.
(c) Explain the transmission of kappa particles during short duration and long duration conjugation in Paramoecium sp. with suitable diagrams. 4+2+4
4. (a) Describe the process of mutation detection in Drosophila by ClB method.
(b) Explain the structure and functions of IS element in bacteria.
(c) Compare and contrast between isoallele and multiple allele with example. 4+3+3
(b) Explain the structure and functions of IS element in bacteria.
(c) Compare and contrast between isoallele and multiple allele with example. 4+3+3
5. (a) Define duplication with suitable example from Drosophila.
(b) Explain 'complementation' in the light of Benzer's rII locus experiment.
(c) Define 'recon' and 'muton'. 3+5+2
(b) Explain 'complementation' in the light of Benzer's rII locus experiment.
(c) Define 'recon' and 'muton'. 3+5+2
6. (a) With a suitable experiment, demonstrate that the white eye colour gene is linked to the X chromosome in Drosophila.
(b) Explain the process of occurrence of mutations by base analogue.
(c) Define penetrance and expressivity. 5+3+2
(b) Explain the process of occurrence of mutations by base analogue.
(c) Define penetrance and expressivity. 5+3+2
7. In Drosophila, Dichaete (D) is a mutation on chromosome III with a dominant effect on wing shape. It is lethal when homozygous. The genes ebony body (e) and pink eye (p) are recessive mutations on chromosome III. Flies from a Dichaete stock were crossed to homozygous ebony, pink flies, and the F1 progeny, with a Dichaete phenotype, were back crossed to the ebony, pink homozygotes.
Using the results of this backcross shown in the table, (a) Diagram this cross, showing the genotypes of the parents and offspring. (b) What is the sequence and interlocus distance between these three genes? (c) Calculate interference and CC. 2+(2+4)+2
Using the results of this backcross shown in the table, (a) Diagram this cross, showing the genotypes of the parents and offspring. (b) What is the sequence and interlocus distance between these three genes? (c) Calculate interference and CC. 2+(2+4)+2
| Phenotype | Number |
| Dichaete | 401 |
| ebony, pink | 389 |
| Dichaete, ebony | 84 |
| pink | 96 |
| Dichaete, pink | 2 |
| ebony | 3 |
| Dichaete, ebony, pink | 12 |
| wild type | 13 |
8. (a) With suitable illustration, explain Meiotic-I non-disjunction of human chromosome 21 and resulting gametes.
(b) 'Additive alleles at multiple loci influences phenotype in a quantitative manner, but each individual allele segregate according to Mendelian rules'— Explain with example from the polygenic trait controlling kernel colour of wheat. 4+6
(b) 'Additive alleles at multiple loci influences phenotype in a quantitative manner, but each individual allele segregate according to Mendelian rules'— Explain with example from the polygenic trait controlling kernel colour of wheat. 4+6
9. (a) Distinguish between polytene puff and lampbrush loop.
(b) Give one example of Monosomy in Human.
(c) With suitable illustration briefly describe the biochemical mutation detection process in Neurospora crassa. (2+2)+1+(2+3)
(b) Give one example of Monosomy in Human.
(c) With suitable illustration briefly describe the biochemical mutation detection process in Neurospora crassa. (2+2)+1+(2+3)
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