Lecture 36: Extranuclear Inheritance, Maternal Effect
1. What is the effect of a mutation in the bicoid gene in Drosophila?
2) Describe the pattern of inheritance of direction of coiling of the shell of the pond snail Limnea peregra.
3. Briefly describe two distinctly different examples of maternal inheritance.
4. What is a petite mutation in yeast? What metabolic defect is responsible for the peitite phenotype?
5. Describe three different inheritance patterns of petite mutations in yeast, and explain how each is achieved.
6. Distinguish between a neutral petite (rho0) and a suppressive petitite (rho-)in a manner that makes it clear that you know what each is and how they differ.
7. How does the pattern of inheritance of genes on the mitochondrial genome differ from that of dominant sex linked genes? Identify a specific pattern that would distinguish between the two.
8. What properties make mitochondrial genes particularly useful in the study of short-term evolutionary changes in populations?
9. What conclusions have been drawn from studies on human mitochondrial gene sequences? What problems have caused these conclusions to be viewed somewhat cautiously?
10. What is meant by the term "bottleneck" as it is used in genetics? What are some of the likely causes of bottlenecks? What evidence suggests that a bottleneck may have occurred in human evolution?
11. What properties of modern mitochondria suggest that they may have originated as prokaryotic endosymbionts?
12. Explain the dependence of modern aerobic life forms on mitochondria.
13. Describe three distinctly different ways in which uniparental mitochondrial inheritance can be achieved. Based on lectures from earlier in the semester, describe two other ways in which some of the inheritance received by specific individuals can be uniparental.
14. Paternal imprinting and mitochondrial inheritance will both cause maternally-derived genes to be expressed exclusively in the immediate progeny of a mating. How would you distinguish between the two types of inheritance?
15. What is the presumed evolutionary origin of the genome found in chloroplasts.
16. How is a defective chloroplast genome likely to be manifested
phenotypically in a higher plant?
17. What is the basis for claiming that cells in higher plants have three separate but interacting genomes?
18. Describe the role played by kappa particles in Paramecium.
19. Explain why most cells are budding yeast are homoplasmic even when originally derived from a heteroplasmic cross.
20. What reasons may be responsible for the fact that such a high percentage of the genes in a typical mitochondrion code for RNA sequences that are not translated?
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