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View Full Version : Viruses can evolve in parallel in related species



Jovialis
12-04-18, 22:24
Viruses are more likely to evolve in similar ways in related species—raising the risk that they will "jump" from one species to another, new research shows.

Scientists from the universities of Exeter and Cambridge compared viruses that evolved in different species and found "parallel genetic changes" were more likely if two host species were closely related.

The findings suggest that when a new virus appears in a species such as chimpanzees, closely related species like humans may become vulnerable too.

Such jumps, also known as host shifts, are a major source of infectious disease, with viruses such as HIV, Ebola and SARS coronavirus all thought to have jumped into humans from other species.

The researchers used deep sequencing of genomes to track the evolution of viruses in 19 species of flies. "Our findings show that when a virus adapts to one host, it might also become better adapted to closely related host species," said Dr Ben Longdon, of the University of Exeter.

"This may explain in part why host shifts tend to occur between related species. However, we sometimes see the same mutations occurring in distantly related host species, and this may help explain why viruses may sometimes jump between distantly related host species.

"At present we know very little about how viruses shift from one host species to another, so research like this is important if we want to understand and ultimately predict emerging viral diseases."

The fruit flies used in the study were 19 species from the Drosophilidae family, which shared a common ancestor 40 million years ago.

The paper, published in the journal PLOS Pathogens, is entitled: "Host shifts result in parallel genetic changes when viruses evolve in closely related species."

Read more at: https://phys.org/news/2018-04-viruses-evolve-parallel-species.html#jCp


Abstract


Host shifts, where a pathogen invades and establishes in a new host species, are a major source of emerging infectious diseases. They frequently occur between related host species and often rely on the pathogen evolving adaptations that increase their fitness in the novel host species. To investigate genetic changes in novel hosts, we experimentally evolved replicate lineages of an RNA virus (Drosophila C Virus) in 19 different species of Drosophilidae and deep sequenced the viral genomes. We found a strong pattern of parallel evolution, where viral lineages from the same host were genetically more similar to each other than to lineages from other host species. When we compared viruses that had evolved in different host species, we found that parallel genetic changes were more likely to occur if the two host species were closely related. This suggests that when a virus adapts to one host it might also become better adapted to closely related host species. This may explain in part why host shifts tend to occur between related species, and may mean that when a new pathogen appears in a given species, closely related species may become vulnerable to the new disease.


https://www.biorxiv.org/content/early/2018/01/12/226175