Reading Comprehension

PT145 · S1 · P4 · Q25 Genetic Typos

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The French biologist Jean-Baptiste de Lamarck (1744–1829) outlined a theory of evolutionary change in 1809, 50 years before Darwin’s On the Origin of Species.

Topic

The revival of Lamarckian evolutionary theory through new research on heredity in the immune system.

Framework

Old / New; Present Debate

Main Point

Edward J. Steele and his team are challenging the widely dismissed Lamarckian theory of evolution by proposing that a mechanism in the immune system could allow acquired traits to be inherited, although most biologists remain skeptical due to lack of direct evidence. ( — End of P1 gives the core new idea, while P4 presents ongoing skepticism and the debate.)

P1: Introduction to Lamarck and Steele's Revival

Lamarck, a French biologist, suggested in 1809 that organisms could inherit traits acquired during their lifetimes. While this idea has been mostly laughed off by modern biologists, Edward J. Steele is now trying to bring Lamarckism back, claiming he’s found supporting evidence in how our immune system works.

P2: The Immune System’s Mutating Genes

This paragraph lays out the mystery of how the immune system adapts so quickly to new threats—partly by certain cells mutating their genes at an unusually high rate, creating "typos" as the DNA is copied to RNA. This enables the immune system to experiment with defenses on the fly.

P3: Steele’s Lamarckian Hypothesis and Its Mechanism

Here we get the details of Steele’s theory: he proposes that altered RNA is turned back into DNA (a process called "reverse transcription"), and suggests that viruses could carry this altered DNA into reproductive cells—potentially passing acquired traits to offspring.

25.

The passage most strongly suggests that the author would agree with which one of the following statements?

Contrary to the opinion of
Too Strong: probably can be passed
The author isn't this far in favor of Steele that she'd be ready to say, "Okay, I'm basically convinced. Some acquired traits probably do get passed from one generation to the next". The last couple paragraphs are saying, "We know that mutated RNA can reverse transcribe back into modified DNA (so experience does have the power to change your DNA), but we're not sure if that modified DNA can actually make it into the reproductive cells and thus be passed on. Steele thinks a virus can do it, but biologists are not convinced by that yet."
3% picked this
Correct
Steele and his colleagues have
Why this is right
This is supported by the first two sentences of the 3rd paragraph: Steele hypothesizes that the altered RNA then reverts back into DNA. If Steele and colleagues had actually observed this reverse transcription, then there would be no need to use the verb 'hypothesizes', which sort of means 'guesses'. Indeed, such "reverse transcription" of RNA back into DNA has been observed frequently in other contexts. What are these other contexts where reverse transcription has been observed? They must be other than in the context of the immune system, since the immune system is what we were talking about throughout paragraph 2. The combination of "we've seen this elsewhere" with "Steele hypothesizes that this is going on in the immune system" suggests that Steele has not directly observed this happening in immune cells.
Skill tested: Author Opinion · how this choice captures the passage's function is the move to repeat next time.
59% picked this
The patterns of mutations concentrated
Wrong Point of View
This is Steele and colleagues' point of view in the final paragraph. The author does not seem to be fully on board with this interpretation yet. We can surmise this because of how the final paragraph is organized. 1. The author skeptically asks, "but does this ever happen in real life?" 2. Steele & Co. claim to have found evidence. They claim that a pattern of mutations blah blah blah. 3. Other biologists are not swayed. They suggest there may be less radical explanations. The author is willing to concede the possibility that Steele is correct, but she still finds his interpretation of these patterns of mutations to be a pretty radical one, and she gives the final word to biologists who are skeptical of it, so she is choosing to leave us with that very ambivalent feeling.
4% picked this
The passing on of acquired
Too Strong: probably confined
We can't really put our finger on any point in the passage where the author is saying, "If there is any passing on of acquired characteristics, then it's probably only found in the immune system." Just because this passage, which spotlights the work of an immunologist (Steele), only talks about acquired characteristics being passed on within the immune system doesn't mean that our author thinks, "Were there to be acquired traits passed on, they would probably only be relating to the immune system".
9% picked this
Unless a hypothesis can be
Opposite, if anything
The second sentence of the final paragraph seems to make an allowance for the fact that when it comes to the science of evolutionary theory, we never observe it directly: we must make do with circumstantial evidence The author is not mad that Steele only has circumstantial evidence. She is saying, "yes, that's to be expected of evolutionary science". If this answer were what the author believed, then she would consider evolutionary theory to be speculation, not science, and that is a very radical view to attribute to any scientific thinker.
25% picked this

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