This is an instructional page, you will find the question choices listed on page 2 of this document. Please read all of the instructions before completing the assignment. Your answer should be 150-200 words. This is not a hard limit, but if you go over or under, make sure it is justified by the quality of your answer.

Here is some general guidance for these assignments:
When you have chosen your question, think carefully about your answer before you begin writing. Try to summarize it as clearly and concisely as you can – one sentence is a reasonable goal for a summary statement. 
The rest of your writing should be carefully structured to support your answer using theory or data from class(es), the paper, or other sources. If you want to reference results from another paper, please provide a full citation. If you want to reference a paper we have previously read in class, an in-text citation is adequate.
Evaluate each sentence independently as either supportive or peripheral to your summary answer and edit your writing accordingly. When you have finished supporting your answer, you are done. There is no need to end your short answer with a concluding summary statement, though it is always a good idea to end on a strong point. If possible, try to allow for a lengthy break, e.g. a night’s sleep, between completing your assignment and submitting. A final proofread after a break often catches mistakes that get missed the first time through.

Question choices for written assignment 5, Haensch et al. 2010

1) The authors state early in this paper that there are three biovars of Yersinia pestis thought to be responsible for three major plague pandemics, but that it is not yet confidently resolved exactly which biovars were responsible for each. Why is it important to know the specific biovar responsible for each pandemic?
2) Three Y. pestis gene fragments were amplified from ancient DNA – pla, caf1, and rpoB – and their sequences are virtually identical to modern Y. pestis samples. Given what we’ve learned about bacterial substitution rates in lecture, does this agree with your expectations for nearly 700 years of evolution? Why or why not?
3) Contamination is a major concern in ancient DNA studies. What are some of the controls the authors used to ensure their PCR reactions were not amplifying contaminant DNA from the grave site or the laboratory? Are you convinced that the Yersinia sequences generated from the “plague pit” samples in this study truly originate from the ancient genomes of the Black Death-causing bacteria?