Talk:Symbiogenesis/GA1

GA Review

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Reviewer: OliveYouBean (talk · contribs) 06:22, 17 December 2022 (UTC)

G'day! This article looks like a really interesting topic so I'm excited to review it. I'm definitely not an expert in biology, so please bear with me if I have to ask any stupid questions.

On the whole, the article looks pretty good. It did take me a few reads of some sentences to understand what they were saying, but I think that's more down to the nature of the topic than how it's written. I'll add notes later in the table below if I think there's anything that needs to be improved. OliveYouBean (talk) 06:22, 17 December 2022 (UTC)

Many thanks for taking this on.... replied to all comments to date. As the holiday season is now upon us, there will be slight delays here and there in my editing. By the way, it's a bit awkward editing inside a table cell like this (and almost impossible to view on a small screen, too), so maybe put the list of detailed comments before the table? Chiswick Chap (talk) 10:41, 20 December 2022 (UTC)

No worries about any delays, I'm not in a rush (plus I may be a little slow myself for similar reasons). I'll move the detailed comments out of the table to make that side of things easier. OliveYouBean (talk) 04:10, 21 December 2022 (UTC)

Collapsing detailed notes that have already been dealt with.

1a detailed notes: Lead: In paragraph 1, the final sentence says that "chloroplasts seem to be related to nitrogen-fixing filamentous cyanobacteria." Including two technical adjectives here ("nitrogen-fixing" and "filamentous") is going to make this harder for an average reader to understand. It's also my understanding from the article's sources (correct me if I'm wrong) that it's still not clear exactly which kinds of cyanobacteria are most closely related to chloroplasts. Given this, I think it'd be better for readability to leave the adjectives out and just say that chloroplasts are related to cyanobacteria, then when this is mentioned later in the article to elaborate on which kinds of cyanobacteria are probably most closely related to chloroplasts. Done. In paragraph 3: "Among the many lines of evidence supporting symbiogenesis are that new mitochondria and plastids are formed only through binary fission, and that cells cannot create new ones otherwise" To someone who doesn't know what binary fission is, this sentence doesn't make it clear why this is evidence. Since this is still the lead section, I think it would help to have something just in parenthesis to clarify that bacteria use binary fission to reproduce and eukaryotes don't. Reworded. History: In paragraph 1: "Mereschkowski knew of the work of botanist Andreas Schimper, who had observed in 1883 that the division of chloroplasts in green plants closely resembled that of free-living cyanobacteria, and who had himself tentatively proposed (in a footnote) that green plants had arisen from a symbiotic union of two organisms." This is a long sentence with a lot of clauses in it. I think this could be simplified by a) explaining Schimper's contributions before Mereschkowski's (that way it doesn't all have to be in past perfect tense), and b) splitting it up into two sentences, e.g. "Andreas Schimper observed in 1883 that... free-living cyanobacteria. He tentatively proposed..." Split. In paragraph 2: "These theories did not gain traction until more detailed electron-microscopic comparisons between cyanobacteria and chloroplasts (for example studies by Hans Ris published in 1961 and 1962[15][16]), combined with the discovery that plastids and mitochondria contain their own DNA[17] (which by that stage was recognized as the hereditary material of organisms) led to a resurrection of the idea of symbiogenesis in the 1960s." - again a long sentence with many clauses. I think it could be better to have a short/simple topic sentence like "These theories did not gain traction until the 1960s." followed by separate sentences for the two pieces of evidence (the electron-microscopic images and the discoveries of mitochondrial/plastid DNA). Split. In paragraph 3: Does this need to be a separate paragraph? I think that giving the second paragraph a topic sentence of "These ideas didn't get traction until the 60's" and a closing sentence of "These ideas are now widely accepted" is a good way to bookend a single paragraph, and would avoid having a single-sentence paragraph at the end. This is just a personal choice though, I don't mind if it stays as is. Closed up. From endosymbionts to organelles: I've just realized here that the article never actually explains what an "endosymbiont" is. This is something where to some readers it'll be obvious from the name, but to others it won't. It could even be confusing to some since it's so similar to the word "endosymbiosis". It might be a good idea here to just give a brief definition of the word to aid the reader. Added. The two words you quote are indeed about the same process, the first being the organism involved and the second being the process. In paragraph 1: "The host cell and organelle need to develop a transport mechanism that enables the return of the protein products needed by the organelle but now manufactured by the cell." is a bit of a stray sentence. It does relate a bit to the rest of the paragraph, but it's the only mention in the paragraph of a transport mechanism; the rest is just about the difference between an organelle and an endosymbiont. Joined it on to the end of the preceding paragraph, where it belongs. I also think this paragraph is overly large. It could be split after "...13 of which are proteins." and then a new paragraph started with "Keeling and Archibald argue that genome size is not the only possible criterion..." This would give one paragraph about genes being transferred and one paragraph about key processes being taken over by the host cell. Split. In paragraph 2: "Taking into account the entire original endosymbiont genome, there are three main possible fates for genes over evolutionary time." this is a sentence that has bugged my brain each time I try to read the article. The first two fates are brought up immediately, but the third isn't mentioned until several sections later. This is confusing because a) someone just reading this section will wonder why the third fate isn't mentioned, and b) someone just reading the "Organellar genomes" section will wonder what the first two fates were. I think it's a good idea to briefly mention the third fate here, then in the later section to not refer to it as the "third and final" fate but just introduce the section as talking about those genes that do remain in the organelle. Done. In paragraph 3: "The mechanisms of gene transfer are not fully known; however, multiple hypotheses exist to explain this phenomenon." I think it might aid the reader to have the next sentence be "The possible mechanisms include..." and then list those that the article mentions. Then have a paragraph break before explaining the cDNA hypothesis. That way you have a paragraph saying "there are several hypotheses" followed by a paragraph for each hypothesis. It might even be helpful to add a "Possible mechanisms for gene transfer" subheading above this paragraph. Done. The paragraph about Ford Doolittle is... confusing? I can't figure out the right word to describe it. Disjointed maybe? It feels like it repeats some information from earlier in the section and doesn't actually explain what the proposed mechanism is. It doesn't address the question of the previous paragraphs about whether it's DNA or RNA that transfers the genes. Is this its own completely separate mechanism, or is it related to one of the other hypotheses? From reading the article I have no idea, and the source for this paragraph barely mentions DNA or RNA. Reworded. Doolittle's "ratchet" would operate whichever transfer mechanism applied, i.e. it's a bit of evolutionary logic, not a separate mechanism. The final paragraph of this section is a bit out of place. In my opinion, it's chronologically/logically the first step of the process to say what the endosymbionts originally were, so it should come before explaining how the endosymbionts became organelles. I think this paragraph should be moved to the beginning of the section instead of the end. Rearranged. Will give suggestions for the rest of the sections later. 1b detailed notes: MOS:LEAD: I believe that per MOS:CONTEXTLINK the word "evolutionary" in the first sentence should be wikilinked to Evolution. The world organelles should probably be wikilinked the first time it is used, as well. Added. MOS:ALTNAME also says that alternative names in the first sentence should be in parentheses. Done. In the first paragraph, saying what the organelles "seem" to be related to feels a bit hedgy, is there another way to phrase it? (Like "[evidence] indicates mitochondria are phylogenetically related to...) Edited.

Further notes on 1a:

Endosymbiosis of protomitochondria

The first sentence of the "Mitochondria" subsection introduces a few technical terms without explanation. Definitely need to say what ATP stands for and wikilink it, probably also worth wikilinking "metabolizing" and "macromolecule" (even though macromolecule is self-explanatory).

Linked and glossed.

While I don't think every technical term needs to be explained (otherwise this section would go forever and be nearly unreadable), since vesicles are mentioned a few times and pretty important I think it would help to just give a brief explanation of what they are. Maybe just putting something in brackets after the first time they're mentioned.

Linked.

In the endomembrane system section, I think finishing off the last sentence with "the endoplasmic reticulum and the Golgi apparatus, both being parts of the endomembrane system" would help. That way a reader isn't required to interpret the supporting image or go to the respective articles to know what their relevance is.

Done.

Organellar genomes

Cytosol should be wikilinked the first time it's mentioned.

Linked.

Secondary endosymbiosis

This sentence in paragraph 2: "A possible secondary endosymbiosis has been observed in process in the heterotrophic protist Hatena behaves like a predator until it ingests a green alga, which loses its flagella and cytoskeleton." I think this sentence is missing a word or two. It might be beneficial to split it into two sentences: "...in the heterotrophic protist Hatena. Hatena behaves like a predator..."

Split and edited.

That's all of my notes at this point. I'll read through again after these are dealt with to make sure I haven't overlooked anything, but otherwise things look really good. Great work on the article! OliveYouBean (talk) 05:08, 21 December 2022 (UTC)

Rate	Attribute	Review Comment
1. Well-written:
	1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct.	In terms of spelling and grammar, there's no issues I can see. I also think that the prose is concise. Most of my notes for this section are going to focus on readability. Since this is a highly technical topic I don't expect everything to be accessible to e.g. young children, but there are cases where I think readability can be improved without losing meaning. If you disagree with any of these suggestions, I'm happy to hear why and fully open to changing my mind.
	1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation.	I believe this is all good now. :)
2. Verifiable with no original research:
	2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline.	All good. :)
	2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose).	In the lead section, the very first ref to this link isn't working for me, so I can't check what it is/whether it's a reliable source. Added archive link. The rest of the sources are all good, though. :)
	2c. it contains no original research.	All good. :)
	2d. it contains no copyright violations or plagiarism.	Copyvio check did come up as matching a few of the dot points from the "Evidence" section word-for-word with this link here [1], I'm going to look through the history to check which way the c/p was done. Slideplayer habitually copies Wikipedia articles for images and texts. No other issues here, though. :)
3. Broad in its coverage:
	3a. it addresses the main aspects of the topic.	All good. :)
	3b. it stays focused on the topic without going into unnecessary detail (see summary style).	I'm a bit iffy on the three paragraphs about different hypotheses for gene transfer mechanisms, but I can't think of how you'd cut that down without leaving out all the contextual information that feels like it needs to be there. It's a lot of detail, but I don't think it's unnecessary detail, so imo it's all good on this criterion. Noted.
	4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each.	All good. :)
	5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute.	All good. :)
6. Illustrated, if possible, by media such as images, video, or audio:
	6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content.	All good. :)
	6b. media are relevant to the topic, and have suitable captions.	All good. :)
	7. Overall assessment.

Thanks for all of your work on the article! I've just done one last read through and made a couple of edits to fix minor issues. I'm happy that you've addressed all of the concerns I had, and I'm satisfied that the article passes the criteria. :) OliveYouBean (talk) 02:08, 22 December 2022 (UTC)