Question

Difficulty: MediumAuthor Attitude and Tone Inferences

For decades, plant biologists maintained that transgenerational epigenetic inheritance—the transmission of DNA methylation patterns without alteration to the underlying nucleotide sequence—was merely an ephemeral secondary phenomenon in wild populations. Early experimental models suggested that stress-induced epigenetic marks were rapidly reset during meiosis, leading scholars such as Dr. Aris Thorne to dismiss their evolutionary significance as negligible compared to classical genetic mutations.

However, recent studies of clonal alpine flora have challenged this orthodoxy. By analyzing hyper-methylated loci in wild plant populations across varying elevations, researchers demonstrated that certain environmentally triggered epigenetic modifications persist across multiple generations, providing a rapid mechanism for adaptive phenotypic plasticity. Thorne's detractors argue that these findings fundamentally undermine classical neo-Darwinian models by proving that soft inheritance plays a primary role in speciation.

Yet, this sweeping conclusion requires careful qualification. While the empirical evidence of multi-generational persistence is compelling, Thorne’s initial skepticism was not entirely unfounded. Most documented epigenetic lineages still exhibit eventual decay over extended generational timelines, and their long-term evolutionary permanence remains unverified. Rather than replacing genetic variation as the engine of natural selection, epigenetic inheritance appears to function as a crucial temporary buffer, enabling populations to survive acute environmental shifts while slower genetic adaptations accumulate. Thus, while Thorne’s outright dismissal of epigenetic inheritance is overly reductive, viewing it as a full replacement for genetic selection overstates the current empirical evidence.

Which of the following best describes the author's attitude toward Thorne's view on the evolutionary significance of transgenerational epigenetic inheritance?

  1. Critical of Thorne's rejection of epigenetic inheritance, while acknowledging that his skepticism regarding its long-term evolutionary permanence has partial merit.Answer
  2. B
    Unreservedly hostile, condemning Thorne's methodology as scientifically obsolete and entirely invalid.
  3. C
    Fully supportive, endorsing Thorne's position that soft inheritance plays no role whatsoever in plant adaptation.
  4. D
    Aligned with Thorne's detractors in claiming that Thorne's research has been completely disproved by recent alpine flora studies.
  5. E
    Indifferent and neutral, viewing the debate between Thorne and his critics as irrelevant to modern evolutionary biology.

Answer

The author is critical of Thorne's rejection of epigenetic inheritance, while acknowledging that his skepticism regarding its long-term evolutionary permanence has partial merit.
The correct response accurately reflects the author's balanced critique. In the final paragraph, the author describes Thorne's total rejection of epigenetic inheritance as 'overly reductive' (indicating criticism), while simultaneously observing that Thorne's skepticism was 'not entirely unfounded' due to the generational decay of epigenetic marks (indicating partial agreement with his caution).

Step-by-Step Solution

1
Locate references to Dr. Aris Thorne's view in the passage.
Thorne dismissed the evolutionary significance of epigenetic inheritance as negligible compared to genetic mutations (Paragraph 1).
Identifying the target figure's stance is necessary before evaluating the author's attitude toward it.
2
Analyze structural pivots where the author evaluates Thorne's view.
In paragraph 3, the author notes that 'Thorne’s initial skepticism was not entirely unfounded' but concludes that 'Thorne’s outright dismissal of epigenetic inheritance is overly reductive.'
Author attitude in GMAT RC is frequently revealed near structural transitions and concluding synthesis sentences.
3
Synthesize the author's qualified tone.
The author demonstrates a nuanced perspective: criticizing Thorne's absolute dismissal as overly reductive, yet recognizing that Thorne was right to doubt the permanent, long-term evolutionary role of epigenetics.
Matching this qualified synthesis directly points to the correct choice without falling for extreme or misattributed distractor traps.

Key Concept

Identifying Qualified Author Stance and Tone Inferences
Rate this question