DNA 'fossils' in fish, amphibians, and reptiles reveal deep diversity of retroviruses

June 14, 2018, Public Library of Science
Retroviruses, a broad category of viruses that infect humans and other vertebrates, have much greater diversity than previously thought, according to new research presented in PLOS Pathogens by Xiaoyu Xu and colleagues at Nanjing Normal University, China. Credit: Xu X, et al. (2018)

Retroviruses, a broad category of viruses that infect humans and other vertebrates, have much greater diversity than previously thought, according to new research presented in PLOS Pathogens by Xiaoyu Xu and colleagues at Nanjing Normal University, China.

Retroviruses include HIV and other viruses that cause disease in many different vertebrate . Most retrovirus research has focused on mammals and birds, but also infect many other vertebrates. Thus, the overall and deep evolutionary history of retroviruses has been murky.

To improve understanding of retroviruses, Xu and colleagues examined molecular "fossils" in vertebrate DNA. These "fossils" can arise from the normal infection cycle of retroviruses: retroviruses store their genetic information in RNA, but when they infect a vertebrate cell, they transcribe their RNA into DNA that integrates into the host . If this occurs in a vertebrate reproductive cell, the viral code can be preserved and passed down to offspring through many generations. The preserved genetic code is known as an endogenous .

The researchers looked for and analyzed in the genomes of 72 fish species, 4 amphibians, and 16 reptiles. They identified more than 8,000 endogenous retroviruses and were able to reconstruct full or partial genomes for about 450 of them. These findings greatly expand the number of known retroviruses and suggest that the diversity of non-endogenous retroviruses passing between non-avian/mammalian hosts today may be far greater than currently thought.

Phylogenetic analysis of the genomes suggests that, during their evolution, many of the non-avian/mammalian retroviruses frequently switched from one preferred host species to another. The analysis also shows that retroviruses frequently transmitted between water and land species, suggesting multiple aquatic evolutionary origins.

The 92 vertebrates in this study represent only about 0.2 percent of the diversity of non-avian/mammalian vertebrates, so it is likely that many more endogenous retroviruses remain undiscovered. Uncovering their diversity and evolutionary history could help inform ongoing efforts to predict, prevent, and minimize retroviral disease outbreaks.

Explore further: New knowledge about host-virus coevolution unmasked from the genomic record

More information: Xu X, Zhao H, Gong Z, Han G-Z (2018) Endogenous retroviruses of non-avian/mammalian vertebrates illuminate diversity and deep history of retroviruses. PLoS Pathog 14(6): e1007072. doi.org/10.1371/journal.ppat.1007072

Related Stories

New tales told by old infections

November 25, 2013

Retroviruses are important pathogens capable of crossing species barriers to infect new hosts, but knowledge of their evolutionary history is limited. By mapping endogenous retroviruses (ERVs), retroviruses whose genes have ...

Retroviruses 'almost half a billion years old'

January 10, 2017

Retroviruses - the family of viruses that includes HIV - are almost half a billion years old, according to new research by scientists at Oxford University. That's several hundred million years older than previously thought ...

French scientists build virus from DNA

November 8, 2006

French scientists have used DNA technology to reconstruct a virus that infected the primate precursors to humans millions of years ago.

Viruses in the genome important for our brain

January 12, 2017

Over millions of years, retroviruses have been incorporated into human DNA, where they today make up almost 10 per cent of the total genome. A research group at Lund University in Sweden has now discovered a mechanism through ...

Recommended for you

Engineered metasurfaces reflect waves in unusual directions

February 18, 2019

In our daily lives, we can find many examples of manipulation of reflected waves, such as mirrors, or reflective surfaces for sound that improve auditorium acoustics. When a wave impinges on a reflective surface with a certain ...

Sound waves let quantum systems 'talk' to one another

February 18, 2019

Researchers at the University of Chicago and Argonne National Laboratory have invented an innovative way for different types of quantum technology to "talk" to each other using sound. The study, published Feb. 11 in Nature ...

Solid-state catalysis: Fluctuations clear the way

February 18, 2019

The use of efficient catalytic agents is what makes many technical procedures feasible in the first place. Indeed, synthesis of more than 80 percent of the products generated in the chemical industry requires the input of ...

Design principles for peroxidase-mimicking nanozymes

February 18, 2019

Nanozymes, enzyme-like catalytic nanomaterials, are considered to be the next generation of enzyme mimics because they not only overcome natural enzymes' intrinsic limitations, but also possess unique properties in comparison ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.