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Unformatted text preview: Problem Set 5 Essay/Thoug ht-Pro voking Qu estion Format
1) What types of DNA sequences are found in the fast, intermediate and slow annealing components in renaturation studies? 2. What molecular events can result in gene duplication? Why is additional duplication more likely once the first duplication has occurred? 3. What can happen to the two functional copies of a gene after a gene duplication event? 4. A new fungus has been isolated and named Wishida washdit. You begin a study of the new fungus Wishida washdit and its actin genes. 1 (a) First, you probe a Southern blot of the W. washdit DNA with a labeled probe complementary to a highly conserved region of the actin gene. You find two bands that hybridize strongly with your probe and one band that hybridizes weakly. Propose an explanation for this hybridization pattern. (b) You now determine the nucleotide sequence of all three actin genes. ACT1 and ACT2 are identical at 88% of the nucleotides, while ACT3 is identical to ACT1 at 43% of the nucleotides. What can you conclude about these actin genes? Multiple Choice Format
1. After a gene is completely duplicated, A. both copies are likely to continue to produce the same protein indefinitely. B. both copies may remain active if one evolves to produce a different functional polypeptide. C. the original copy is more likely to become inactive than is the new copy. D. it is very unlikely that one copy will become inactive. E. it is unlikely that further duplication of the gene will take place. 2. Human hemoglobin A. is expressed in only two different forms at no more than two different developmental stages. B. is expressed in only one form at a time. C. is expressed as a dimer of two different polypeptides. D. is coded by genes in two related gene clusters. E. is coded by two unrelated genes. 2 3. Globin genes have evolved by A. sequence evolution via point mutations in genes. B. tandem duplications of genes. C. fusion of exons of a gene. D. translocation of a gene copy to a new chromosome. E. All of the above mechanisms have contributed to globin gene evolution. 4. The degree of divergence between two homologous DNA sequences can be used to estimate the time of the common ancestor of the two sequences if A. they have been evolving at a constant rate. B. the rate of silent site evolution is greater than that of replacement site evolution. C. the rate of silent site evolution is the same as that of replacement site evolution. D. the rate of silent site evolution is less than that of replacement site evolution. E. the rate of DNA sequence evolution has decreased over time. Short A nswe r/Fill in the Blank Fo rmat
1. Multiple 110 bp tandemly repeated sequences are called ____________________. 2. A DNA sequence that is homologous to a functional gene but does not produce a functional polypeptide because of deficiencies in transcription or translation of the gene is called a(n) ________________________. 3 3. _______________________ is a disorder that results from deletions in the a-globin or b-globin gene clusters. 4 ...
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- Fall '09
- DNA, 43%, actin genes, W. washdit DNA, replacement site evolution