Where did viruses come form?

Answer 1

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Tracing the origins of viruses is difficult because they don't leave fossils and because of the tricks they use to make copies of themselves within the cells they've invaded. Some viruses even have the ability to stitch their own genes into those of the cells they infect, which means studying their ancestry requires untangling it from the history of their hosts and other organisms. What makes the process even more complicated is that viruses don't just infect humans; they can infect basically any organism-from bacteria to horses; seaweed to people.

Still, scientists have been able to piece together some viral histories, based on the fact that the genes of many viruses-such as those that cause herpes and mono-seem to share some properties with cells' own genes. This could suggest that they started as big bits of cellular DNA and then became independent-or that these viruses came along very early in evolution, and some of their DNA stuck around in cells' genomes. The fact that some viruses that infect humans share structural features with viruses that infect bacteria could mean that all of these viruses have a common origin, dating back several billion years. This highlights another problem with tracing virus origins: most modern viruses seem to be a patchwork of bits that come from different sources-a sort of "mix and match" approach to building an organism.

The fact that viruses like the deadly Ebola and Marburg viruses, as well as the distantly related viruses that cause measles and rabies, are only found in a limited number of species suggests that those viruses are relatively new-after all, those organisms came along somewhat recently in evolutionary time. Many of these "new" viruses likely originated in insects many million years ago and at some point in evolution developed the ability to infect other species-probably as insects interacted with or fed from them.

Answer 2

Viruses are thought to have originated from genetic elements that evolved independently from cellular organisms. They likely emerged as genetic material that escaped from host cells and evolved to become infectious particles capable of replicating within host cells. The exact origins of viruses remain a subject of ongoing research and debate in the scientific community.

Answer 3

existing cell parts

Scientists suggest that viruses are NUCLEIC ACIDS that break free from their host cells, but can still replicate.