Principle of Genetics (2+1) GPB-501 (Question Paper )

  

 

I Define/Explain the following (1 x 5 = 5)

1. Multiple allelism
2. Pleiotropism
3. Sex influenced traits
4. Second order segregation
5. Hardy Weinberg equilibrium

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II Substantiate the following (2 x 5 = 10)

1. Three point test cross process is efficient in determining relatively precise map distances.
2. NIL’s, RIL’s and DH serve as excellent breeding material for DNA marker related studies.
3. Test cross process enables phenotyping gametes.
4. Digenic/trigenic epistatic/nonepistatic gene interaction is not considered as an exception to Mendelian rules of inheritance.
5. Thomas Hunt Morgan’s discovery of mutant white eye in Drosophila had to be supported with Calvin Bridges' efforts to prove physical basis of inheritance.

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III Differentiate between the following (3 x 5 = 15)

1. Complete linkage and independent assortment
2. Complete dominance and No dominance
3. X-linked and pseudo-autosomal inheritance
4. Qualitative and quantitative traits
5. Maternal effect and Maternal inheritance

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IV Answer the following (5 x 5 = 25)

1. Explain cytological evidence to demonstrate that the F1 plant heterozygous for two pairs of alleles will produce four types of gametes in equal frequencies.
2. Explain the experiment carried out by Creighton and McClintok to explain the cytological basis of crossing over.
3. List out various mechanisms of sex determination in animals. Explain fix determination in Drosophila assuming chromosomal as well as genetic balance theory of sex determination.
4. Explain cross-cross inheritance of sex linked genes by taking example of inheritance of white eye colour in Drosophila.
5. Explain how inheritance of leaf variegation is different from inheritance of traits governed by nuclear genes.