Sbt2254:General Genetics Question Paper
Sbt2254:General Genetics
Course:Bachelor Of Crop Protection
Institution: Meru University Of Science And Technology question papers
Exam Year:2012
QUESTION ONE (30 MARKS)
a) Differentiate between mendelian and non-mendelian inheritance. (4 Marks) b) Using a diagram, distinguish between cis and trans-arrangement. (4 Marks) c) Explain giving examples what is meant by the following terms. (8 Marks) i. Genomic imprinting ii. Dosage compensation iii. Epistasis iv. Polygenic inheritance d) In Drosophila melanogaster, 2n is 8. How many linkage groups are in? (4 Marks) i. A female a Drosophila melanogaster, fruit fly ii. In a male Drosophila melanogaster fruit fly e) The data below shows c-sh linkage in corn with reported map distances for 3 genes, c(colourless aleurone), sh(shrunken grains) and wx(waxy endosperm) and cross-over frequencies. Region genes frequency % cross over map distance in of cross-overs map unit 1 C sh 0.034 3.4 (3.4+0.1) = 3.5 11 sh wx 0.183 18.3 (18.3+0.1)=18.4 Double crossover c.sh.wx 0.001 0.1 i. From the above data, calculate the co-efficient of coincidence. (3 Marks) ii. What is meant by the term interference (2 Marks) iii. Name two genetic markers. (2 Marks)
f) A hypothetical series of 20 multiple alleles is known for a certain locus.
2
g) i) How many phenotypic classes are possible? (2 Marks) ii) How many different genotypic classes are possible? (1 Mark)
QUESTION TWO (20 MARKS)
Discuss the Hardy-Weinberg principle of genetic equilibrium. (20 Marks)
QUESTION THREE (20 MARKS)
Describe cloning of DNA in plasmids. (20 Marks)
QUESTION FOUR (20 MARKS)
Discuss various sources and maintenance of variation in crop improvements. (20 Marks)
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