Assignment 1:3 Peer Review of CRISPR-Cas9 (Aleem Tariq)

TO: Aleem Tariq

FROM: Syed Waqar Ahmed

DATE: 5^th October 2020

SUBJECT: Review of Your Definitions Assignment

I have reviewed your Definitions assignment on CRISPR-CAS9. Your explanation of how CRISPR works was methodical and elegant. The visuals you used were very well chosen and help the reader to understand both the structure and function of CRISPR. I would like to offer the following suggestions:

Comments about purpose: The purpose of your expanded definition is to help the marketing director learn more about CRISPR so they can convince an audience of a board of directors to invest in this technology. Keeping that purpose in mind, there needs to be further elaboration of why CRISPR is better than other ways of genome editing. You have mentioned that CRISPR is more accurate but you should also comment on the favourable aspects of its efficiency, speed and economics. Furthermore, you should provide at least one substantive example of a successful use in industry or medicine.

Use of jargon: In the third paragraph of your expanded definition you used the terms “palindromic repeats” and “arrays”. The biological and context-specific meaning of these terms might not be correctly interpreted by non-biologists and so these terms should be further clarified.

Organization: You start with the importance of CRISPR as a gene-editing tool and touch upon the importance and applications of CRISPR at the end. However, for a non-biologist audience the whole write-up would be more impactful if you explain the relevance of gene-editing to science, industry and human health at the start rather than the end.

I feel that your parenthetical definition is too explanatory. From my reading of Gurak, a parenthetical definition should be briefer, something akin to, “CRISPR-CAS9 is a gene-editing technology”.

Research: Your research sources were well selected in that they included an authoritative review article as the scientific backbone, as well as a government/industry publication. Given the breakneck speed of research progress in this field, it was notable that both of these sources were published in the current year.

Visuals: The two images were well selected as they allow the reader to see the structure of a CRISPR-CAS9 unit as well visualize the mechanism of action.

Misc.: I have provided some comments below in reference to extracts from the text which are in italics:

• “sequence of letters: A, G, T, and C”. This might be replaced with “sequence of 4 nucleotides which are represented as A, T, G and C. In RNA the T is replaced by a U.”
• “system was first identified by Francis Mojica”. Inclusion of year of discovery would provide some historical referencing.
• “It’s composed of two parts; a CRISPR array, and a Cas9 system.” The terms “CRISPR array” and “Cas9 system” should be in quotes.
• “This allows the bacteria to “remember” the viruses, analogous to how our immune system works but at a far smaller scale.” It is unclear what is meant by “a far smaller scale”. You should make clear if you are referring to smaller in terms of size or significance or complexity.
• “If a future viral attack occurs, RNA segments from spacers specific to the virus will be produced and attach to the Cas9 protein.” As you describe transcription here, it’s important to keep your non-biologist audience in mind, who may not follow along as we go from DNA to RNA.

I enjoyed reading your introduction to CRISPR. It is an exciting new technology and the focus of a lot of academic and industry interest. Your writeup was well written and well illustrated and cited key publications on the topic. With some minor revisions, it presents an easy-to-read and easy-to-understand summary of a relatively technical topic. Please let me know if you have any questions.

Document that was peer-reviewed 301-Aleem-Tariq-Definitions