Soru

The following passage is adapted from an article about the history of molecular biology:

For decades, the central dogma of molecular biology dictated that infectious agents must contain nucleic acids—either DNA or RNA—to replicate and cause disease. When Stanley Prusiner first proposed in 1982 that the transmissible agent behind scrapie, a degenerative neurological disease, was composed entirely of protein, the scientific community met his hypothesis with profound skepticism. To support his radical claim, Prusiner demonstrated that procedures damaging to nucleic acids, such as ultraviolet radiation, failed to reduce the infectivity of the scrapie agent, whereas treatments that denatured proteins, such as exposure to urea, rendered the agent inactive. Critics argued that the protein-only model violated fundamental biological principles, suggesting instead that a small, hidden virus was the true culprit. However, the subsequent discovery of the gene encoding the prion protein (PrP) in healthy organisms eventually clarified the mechanism: the disease arises when the normal cellular protein misfolds into a pathological, self-propagating shape. By redefining the biochemical basis of infection, the prion hypothesis fundamentally transformed our understanding of neurodegenerative diseases, demonstrating that structural replication could occur in the absence of genetic material.

Which statement best summarizes the author's primary argument in the passage?