Bio 363 Human Genetics, Spring 2013
Sickle cell anemia study sheet
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Why would you consider this a reputable web site?
What is the molecular structure of hemoglobin?
What hemoglobin variants exist in a normal person, and at what life stages do they appear?
What genes encode components of hemoglobin?
What mutant varieties of hemoglobin exist?
What happens to HbS during an oxygenation/deoxygenation cycle? How does damage occur?
How does hydroxyurea help sickle cell patients? How is this mechanism related to differing disease severity in different areas?
What explanations have been proposed for how sickle cell heterozygosity protects against malaria?
Ingram, 2004 :
This paper is a commentary. The purpose is not to relate or summarize new results, but instead to convey a personal perspective and/or new hypothesis.
By what methods did Pauling, initially, and then Ingram and colleagues deduce the structural difference between HbA and HbS?
Why was it important to examine HbS from five different patients?
How did Ingram's results contribute to the emerging knowledge of how DNA sequences specify protein sequences?
What's the difference between sickle cell anemia and thalassemias? (see also background readings)
How might you explain the allele frequencies of HbS and HbC in Suriname and Curacao in 1965? (see bottom of right column, page 4)
Explain the theme of serendipity.
Townes, 2008 :
This is a review paper. Results of several primary research papers are summarized. However, it is not a fully comprehensive review paper, as the author focuses mainly on his own work.
What are the two mouse SCD models that the author and his colleagues have created? Why is one more useful than the other?
What problems can arise with a gene addition strategy? What new strategy have the author and colleagues used to circumvent the problem? Why is this new strategy more difficult overall?
What types of cells are used for 1) the gene addition strategy and 2) the new strategy described in this paper?
What are iPS cells, and how have they been useful in these studies?
What challenges lie ahead for transferring this technology to a human cell system?
What dangers to the patient must be avoided?
Chang et al., 2006:
This is a research paper that reports original data. To start, read the abstract and introduction to get the context and the general questions to be addressed. Then read the discussion to understand how the findings fit within the context. You now know the start and end point of the paper, so delve into the results section to see what experiments led from one point to the other. Each figure will depict a major finding/set of findings. For each figure, read the associated portion of the text AND the figure legend to determine the specific question addressed, the technique used, and the data generated. Don't bother with the materials and methods section unless you need clarification on particular reagents used. Look up unfamiliar terminology in the textbook and online, but don't get bogged down-- I don't expect you to get every detail as you are initially getting used to reading research papers.
What is the overall goal of this study? How is the mouse model used in this study better than the ones described in the review above?
How did the authors create and identify the exact ES cell line they wanted? (see Figure 1, Table 1, and associated text)
What two different DNA constructs were introduced into ES cells? How were homologous recombination events detected (Fig 2)? Find where the restriction enzymes cut and where the probe binds, and then visualize what band sizes would be detected at the original locus vs. the locus that has undergone the homologous recombination.
Why does homologous recombination not automatically guarantee that the mutation is corrected?
How were the recombined cell lines screened to find which had the mutation corrected (Fig 3)? Why was the Bsu36I restriction enzyme so helpful here?
What are monoclonal antibodies? How were they used to test globin production in the various cell lines that were generated? Which cell lines demonstrate the proof of concept that is the main point of the paper? What possibly went wrong in a couple of the cell lines?
Go back and check the references listed at the end of the review paper. Is this paper cited? Should it have been?