Arvind Varsani

With Eugene Koonin, we propose a concept of “the selfish ribosome”, under which evolution of life is viewed as a ribosomal takeover, where the ribosome evolved to consume most of the cell’s resources, while other cellular componentry ensures the propagation of the ribosome. arxiv.org/abs/2602.23268

These wee birds are just zen

Congratulations to Sonomi Yamaguchi for her paper at @nature.com. Sonomi discovered Clover defense and explained how nucleotide signals control each step of viral sensing, immune regulation, and viral restriction – named for her beautiful "four-leaf" structures 🍀

www.nature.com/articles/s41...

Three postdoctoral fellowships in quantitative biology are available as part of a new Quantitative Biology Initiative in the Department of Biology at the University of Maryland.

Best consideration date: 3/14

Job Ad:
umd.wd1.myworkdayjobs.com/en-US/UMCP/j...

Department:
biology.umd.edu/people

Image of a herpesvirus structure

I am excited to share our latest preprint - An evolutionarily divergent herpesvirus with a giant tail. Featuring symmetry breaking and genome annotation from structure using ModelAngelo. doi.org/10.64898/202...

Polyomaviruses are masters of persistence and dissemination: we show there are two forms of long-term persistent PyVs in the kidney: the majority being cryptic (non-shedding) and a minority that actively shed, and these fates are determined shortly after infection.

www.biorxiv.org/content/10.6...

Multiple protein structure alignment at scale with FoldMason Protein structure is conserved beyond sequence, making multiple structural alignment (MSTA) essential for analyzing distantly related proteins. Computational prediction methods have vastly extended ou...

www.science.org/doi/10.1126/...

Transcriptome mining reveals diversity and evolution of circulating and endogenous amphibian retroviruses - Retrovirology Background The evolutionary history of retroviruses and their impact on vertebrate evolution remains poorly understood, particularly in non-mammalian hosts. In this study, we explore retroviruses associated with Amphibia through analysis of 169 RNA sequencing datasets from 102 amphibian species. Using a BLAST-based approach, we identified retroviral transcripts from assembled transcriptomes and phylogenetically characterise both their pol and env regions to elucidate their evolutionary history. Results We identified the transcription of 18 novel and two previously described retroviruses with closest relatives in gammaretrovirus, epsilonretrovirus, betaretrovirus and spumaretrovirinae. Despite their differing pol phylogenies, we found that all amphibian retroviruses belong to the gamma-type envelope group (GTE). This suggests a common selection pressure for amphibian retroviruses to retain GTEs. Within these GTEs we also observed a new clade of alpharetrovirus-like envelopes in amphibians which form a sister clade to avian alpharetrovirus envelopes. Furthermore, we observe correlations between amphibian taxonomical order and retroviral diversity, with Gymnophiona (caecilians) harbouring the widest diversity of retroviruses whilst Anura (frogs and toads) harbour the fewest. Through mapping these transcribed retroviruses to their respective genomes (seven available) supplemented with observing ORF intactness, we determined that 14 of the 20 retroviruses are likely endogenous in origin yet are still transcribed in many amphibian tissues. These amphibian endogenous retroviruses (ERVs) have high genomic copy numbers: most (5/7) ERVs investigated have > 100 copies, and one of which has 9,219 integrations within the Ichthyophis bannanicus caecilian genome. This high retroviral load in amphibian genomes may suggest that these retroviruses have low pathogenicity, or may reflect a lack of transposon control mechanisms in amphibian cells. Conclusions Through the characterisation of metatranscriptomic and genomic data from retroviruses in this study, we provide insights into their evolution in amphibians and exemplify the diversity of Retroviridae in vertebrate genomes. The identification of novel retroviral clades, widespread transcription of endogenous retroviruses in amphibians and abundance of ERV copies suggests that Retroviridae have played a significant role in amphibian evolution.

New study uncovers extensive diversity of circulating and endogenous #amphibian #retroviruses, identifying 20 retrovirus transcripts across 102 species, revealing deep evolutionary patterns in vertebrate hosts.🦎🧬#VirusEvolution
📄 https://doi.org/10.1186/s12977-025-00669-y
👤 EVBC member: Emma Harding

Registration form for iVoM4 After submitting this form, you will receive the instructions to join our webinars at the email address you provide.

New 2026 iVoM series coming up!

Each session includes SCR and 3 ECRs, & plenty of opportunities to interact with the speakers and ask questions.

Sign up for links/updates: docs.google.com/forms/d/1hAB...

First up: Viral Biotechnologies Wed, 28 th January at 17:00 CET / 11:00 EST / 08:00 PST

Stacks of book When Trees Testify by Beronda Montgomery

Grateful to @beaverdalebooks.bsky.social & Des Moines Botanical Garden for an amazing launch event for When Trees Testify: Science Wisdom History and America's Black Botanical Legacy. Amazing group of friends, colleagues, and new acquaintances celebrating this week's launch
#WhenTreesTestify

Ok. Maybe adenos next.

Not really - minimal effort on that if any. All effort on the same gig as usual, penguin ecology project.

She is 20-25 min helicopter ride away from Cape Royds.

Genetic diversity in horseshoe bat ACE2 and sarbecovirus spike proteins mutually shape one another Angiotensin-converting enzyme 2 (ACE2) serves as the entry receptor for a wide diversity of sarbecoviruses naturally harboured by horseshoe bats (genus Rhinolophus ). Despite the extensive circulation...

New preprint led by our MSc student Wenye Li!! 🎉

@systemsvirology.bsky.social

What we find is a historic genetic interplay between sarbecoviruses and their horseshoe bat hosts' ACE2 receptor! 🦇 🧵...

www.biorxiv.org/content/10.1...

A screenshot of the front page of Pathoplexus' website, showing the addition of a tile for Marburg Virus.

1/ 🚀 Pathoplexus now supports Marburg virus (MARV) and Ravn virus (RAVN) (sister viruses in the same genus). MARV has two main clades and causes severe disease with reported fatality rates of 24–88%.

You can read more detail about adding Marburg here: pathoplexus.org/news/2025-11...

Convergent evolution of viral-like Borg archaeal extrachromosomal elements and giant eukaryotic viruses - Nature Communications Borgs are large extrachromosomal elements of anaerobic methane-oxidizing archaea. Here, via in silico protein structure prediction of ~10,000 Borg proteins, the authors reveal that Borgs share numerou...

Out now in Nature Communications: Convergent evolution of viral-like Borg archaeal extrachromosomal elements and giant eukaryotic viruses

www.nature.com/articles/s41...

@luisvalentin.bsky.social @lingdong-shi.bsky.social @martianmicrobe.bsky.social @mschoelmerich.bsky.social

Widespread and intron-rich mirusviruses are predicted to reproduce in nuclei of unicellular eukaryotes - Nature Microbiology Environmental metagenomic explorations show that Mirusviricota lineages lack essential replication and transcription genes and contain spliceosomal introns, suggesting nuclear reproduction.

Check out our latest paper on mirusviruses, one of the most remarkable new groups of protist viruses - extremely diverse, carry lots of spliceosomal introns (including new homing introns) and are at the evolutionary crossroads between tailed phages and herpesviruses! www.nature.com/articles/s41...

📢 New preprint is out on bioRxiv 📢:

How much does virome prep influence our view of the human gut virome?

Short answer: a lot.

Long answer:
doi.org/10.1101/2025...

Different methods lead to distinct community structures, richness, and major virus-host abundance patterns.

🧵 1/5

Avian-origin influenza A viruses tolerate elevated pyrexic temperatures in mammals Host body temperature can define a virus’s replicative profile—influenza A viruses (IAVs) adapted to 40° to 42°C in birds are less temperature sensitive in vitro compared with human isolates adapted t...

How does fever work?

Our new Science paper shows how elevated body temperature can protect against severe influenza and that avian-origin viruses escape this defence.

This is likely one reason why bird flus and some pandemic influenzas can be so severe.🧵

www.science.org/doi/10.1126/...

A Cell So Minimal That It Challenges Definitions of Life | Quanta Magazine The newly described microbe represents a world of parasitic, intercellular biodiversity only beginning to be revealed by genome sequencing.

According to the microbial ecologist Puri López-García, pictured here at a salt flat in the Chilean Andes, some 25% to 50% of all bacterial cells may be parasites of other cells.

Bats and Viruses: Rumour, Intrigue, Deception, and Spectacle Bats as Hyperreal Reservoirs of Viral Disease

"The hyperreal bat: more vivid, more coherent, and more narratively satisfying than any bat in nature."

Why does the idea of bats as special viral reservoirs endure?

New Substack post:

robertjgifford.substack.com/p/bats-and-v...

Biogeography and host interactions of CPR and DPANN viruses in acid mine drainage sediments - Nature Communications The ecological role of viruses for CPR bacteria and DPANN archaea remains understudied. Here, the authors apply metagenomic approaches to study the biogeographic distribution of CPR and DPANN viruses in acid mine drainage sediments and elucidate their complex interplays.

Biogeography and host interactions of CPR and DPANN viruses in acid mine drainage sediments | Nature Communications https://www.nature.com/articles/s41467-025-65461-0

Diversity of polyomaviruses and papillomaviruses in penguins from eastern and western Antarctica Polyomaviruses and papillomaviruses are icosahedral viruses with small circular dsDNA genomes. Limited information on their diversity and evolution in avian hosts is available, with even less known re...

Diversity of polyomaviruses and papillomaviruses in penguins from eastern and western Antarctica - www.microbiologyresearch.org/content/jour...

A group of Adélie penguins in #Antarctica. Photo courtesy Arvind Varsani/ASU.

Studying penguin virology in #Antarctica:
@arizonastateuni.bsky.social researchers lead in discovery of new viruses in Antarctic penguins, expanding knowledge of polar ecosystems @viralnomad.bsky.social

news.asu.edu/b/20251124-s...

Oh no!
🧪🌎🦑🦉🦊

Nice. I will be in CHC on route to the Antarctic early Dec and then mid/late Jan

Congrats

🚨 Another funded PhD alert🚨

We are recruiting again! For a PhD student to start with us in the @langridgelab.bsky.social October 2026 - please share 👀

If you are interested in foodborne pathogens, public health and phage, look no further 🦠🏥🧬

➡️ tinyurl.com/3zvavp2t ⬅️

Apply by 6 Jan 2026 🗓️

Postdoctoral researcher in molecular ecology - Uppsala University Postdoctoral researcher in molecular ecology, Department of Ecology and Genetics, Uppsala University

📢 We have an open position for a postdoc to join my lab. It's a great position @animecol-uu.bsky.social, fully salaried for 2.5 years with all benefits.

www.uu.se/en/about-uu/...

The project is about transmission patterns of bacteria and antimicrobial resistance (AMR) in aquatic insects. 🧬🦠 (1/3)

warwick.ac.uk/fac/cross_fa...

I am advertising for a PhD position in my group. We'll be investigating how pathogenic RNA viruses replicate in the nucleus. The project will teach cryoEM/ET, virus culture, and in vitro assays.

If you're interested reach out and I'd be happy to have a chat.