Loading subject…
There's Evidence for Multiple Origins of Viruses
- Viruses show enormous diversity in structure and genetic composition.
- This diversity suggests that viruses did not arise from a single common ancestor but instead evolved multiple times from different cellular origins.
- Their shared features likely result from convergent evolution, not shared descent.
Note
The genetic code is shared by viruses and cells, which suggests viruses evolved from cellular life, not before it.
Two Hypotheses: How Viruses May Have Arisen
- Progressive (Escape) Hypothesis:
- Viruses may have evolved from mobile genetic elements, like retrotransposons, which move within genomes.
- Retrotransposons and retroviruses (e.g., HIV) both use reverse transcription, where RNA is converted into DNA.
