Sean Leonard

A tripartite protein complex promotes DNA transport during natural transformation in Firmicutes | PNAS Natural genetic transformation is a conserved mechanism of bacterial horizontal gene transfer, which is directed entirely by the recipient cell and...

Pleased to share our recent article in PNAS - a collaboration with @jessicaandreani.bsky.social & Pablo Radicella, with important roles played by many members of each team.

A tripartite protein complex promotes DNA transport during natural transformation in Firmicutes www.pnas.org/doi/10.1073/...

YouTube video by MicrobeTV TWiEVO #120 Livestream 11/26/25 1:00 PM Eastern

One of my favorite preprints of the year from the great @mollyschumer.bsky.social. A foamy virus that makes things sparkle, now up on TWiEVO episode 120 for some podcast peer review www.youtube.com/watch?v=3T65...

Nested Connections: Local Phage and Broad Plasmid Sharing in the Honey Bee Mobilome Honey bees rely on bacterial symbionts for their nutritional needs and for protection against invading pathogens. Genetic diversity among strains within the colony has the potential to impact symbiont...

#microsky #phagesky #phage plasmids & other #MGE in the bee #microbiome

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

Rewiring holobiont systems with synthetic biology Holobionts are complex communities comprising a host and its diverse microbiota. Their intricate relationships are crucial for biological processes like nutrient uptake, immune function, and environme...

Rewiring holobiont systems with synthetic biology
www.cell.com/trends/biote...

Please share this with anyone who may be interested in a post-doc in Germany:

jobs.awi.de/Vacancies/20...

This is quite an exciting opportunity to push the boundaries of what is known regarding the molecular basis of the formation and demise of photosymbiotic relationships in marine habitats.

For population genetics and evolutionary biology folks in the Bay Area: the next BAPG will be hosted by Stanford CEHG and the Petrov lab at Stanford on 12/6.
Registration is free but required. The deadline for talk submission is Nov. 16. Hope to see you soon! Pls RT!
docs.google.com/forms/d/e/1F...

Antiviral reverse transcriptases reveal the evolutionary origin of telomerase Defense-associated reverse transcriptases (DRTs) employ diverse and distinctive mechanisms of cDNA synthesis to protect bacteria against viral infection. However, much of DRT family diversity remains ...

1/10 Genome maintenance by telomerase is a fundamental process in nearly all eukaryotes. But where does it come from?

Today, we report the discovery of telomerase homologs in a family of antiviral RTs, revealing an unexpected evolutionary origin in bacteria.
www.biorxiv.org/content/10.1...

AI still ain’t got it

With Jeff Barrick's return to #MSU, the #LTEE was restarted today after a short pause (frozen) for the move.

Today was daily transfer 12,301. With ~6.6 generations per day, they are now at ~82,007 generations.

100,000 generations is fast approaching! Are you ready, #Spartans?

@msumgi.bsky.social

The ecology and evolution of bacterial immune systems'.

#phage #phagesky

A bunch of interesting reviews

royalsocietypublishing.org/doi/10.1098/...

System architecture of quorum-sensing circuits. Top left: Quorum sensing in proteobacteria. A signal synthase (blue) produces a diffusible signal (black circles) that binds to a cytoplasmic signal receptor (light blue). When the signal reaches sufficient concentrations, it binds to and activates the receptor, which causes changes in transcription of target genes. Top right: The las and rhl systems of P. aeruginosa. The lasB gene is activated by both systems. The specific acyl-homoserine lactone signal molecule is pictured for each system. Bottom: Illustration of circuit architecture: reciprocal, hierarchical, and independent. Indicated below are the relative levels of lasB gene activation and sensitivity shown by Thomas and colleagues in experimental and modeling studies.

Many bacteria use #QuorumSensing to control genes based on population density. @jrchandler.bsky.social &co explore a @plosbiology.org study showing that in P. aeruginosa, 2 QS circuits activate each other, enhancing robustness & explaining redundancy 🧪 Paper: plos.io/3I7DhRG Primer: plos.io/4niSZZd

A pointer and index finger holds up a very small piece of bark with two tiny, flower-shaped fungi growing on it. The fungi are a fraction of the size of the person's fingernail.

A pointer and index finger holds up a very small piece of bark with two tiny, flower-shaped fungi growing on it. The fungi are a fraction of the size of the person's fingernail.

A pointer and index finger holds up a very small piece of bark with two tiny, flower-shaped fungi growing on it. The fungi are a fraction of the size of the person's fingernail.

TINY FUNGUS. Absolutely magical. Specifically, Cannonball Fungus (Sphaerobolus stellatus).

📷 ezatars on iNaturalist
📍 Latvia
🔗: www.inaturalist.org/observations...
#ObservationOfTheDay

A new theme issue of #PhilTransB examines the evolutionary history of bacterial immune systems, their modes of action, and the patterns how different bacterial immune systems are distributed across different ecosystems. Read: buff.ly/Z4qdxY1

Drs @minealtinli.bsky.social‬ @spleonard1.bsky.social‬ @alainkohlvirology.bsky.social & @mosquitomicrobe.bsky.social review #bacteria-mediated #dsRNA delivery for #mosquito-borne #virus control. #RNAi #vectorcontrol #symbiont #engineering #mosquito #arbovirus

www.cell.com/trends/paras...

An old image of a salivary gland chromosome from Drosophila melanogaster, with lines across different segments indicating contact points.

The original circos plot? From the 1947-1948 Carnegie Yearbook, the page prior to McClintock's Mutable Loci in Maize paper.

Homeword Bound With apologies to Rhymin’ Simon

Homeward Bound! Yes, the #LTEE is homeward bound. After a few thousand generations in Texas, the lines are coming back to #MSU, along with Jeff Barrick, and his team. telliamedrevisited.wordpress.com/2025/07/28/h...

#phage #phagesky

Phage-based delivery of CRISPR-associated transposases for targeted bacterial editing | PNAS www.pnas.org/doi/10.1073/...

In case you’re wondering, the “caterpillars are hybrid worms” paper at PNAS remains alive (and guessing won’t be retracted ever)

www.pnas.org/doi/10.1073/...

If you're not taking the time to draw your own horny baseball art, man, what are we doing here. What is the point of being alive if not to draw your own horny baseball fan art?!?!?!

Microbial Databases, Software Tools, and Web Services Publish your microbial database or software tool in MRA to gain recognition, citations, and community trust.

Excited to share our new call for papers at @asm.org's MRA journal. Do you have a database, software, or web-based tool that would be a great resource for the micro community? Consider submitting it to MRA! journals.asm.org/journal/mra/...

De novo mutations mediate phenotypic switching in an opportunistic human lung pathogen - Nature Communications Bacteria evolving within humans employ strategies to overcome trade-offs. Here, the authors report that the cystic fibrosis-associated pathogen Burkholderia dolosa alternates phenotypes in vivo by acc...

How likely are SNP-based phenotypic reversions during human infection/coloniziation?

Our latest paper on the rare CF pathogen B. dolosa -- a great collaboration with folks I've worked with since my PhD and led by Alex Poret -- adds to the evidence that reversions are likely in large populations.

We are on the lookout for postdocs for two different projects at the intersection of ecology, evolution, and the human microbiome.

See thread for more information and reach out!

Macro photo in side view of two rather chubby orange and black insects standing end-to-end, mating, on the top of several pillow-like succulent leaves. The insect at left is slightly smaller, with feathery antennae.

I hope these two purslane sawflies weren't looking for privacy.

Close up of a brownish red fruit fly with bar-patterned eyes, multiple bristles and wings that are brown with transparent edges and circles. It is sitting on a sunflower leaf.

Good morning bright eyes.

Paracantha genera, a tephritid fruit fly. The larvae live inside sunflowers and adults hang around. From the Pollinator Garden just now.
🌿

Sloan Lab Welcome! Our research focuses on the evolutionary process at the molecular level. In particular, we investigate how a mixture of natural selection and non-adaptive forces create and maintain the amazi...

Please share! Our lab is recruiting a PhD student to join us starting fall 2026. Our group is broadly interested in plant molecular evolution and comparative genomics. More info about our lab and grad programs at Colorado St. is available on our lab website.

sites.google.com/site/danielb...

Thank you for reminding me of the delightful luxury of arguing about theoretical symbiosis terminology in this day and age 🥰

The Hologenome Concept: Helpful or Hollow? It is accepted that microbial symbionts are important to the biology of their hosts, but this essay asks what evidence is needed to determine whether symbionts and hosts have coevolved and whether the...

And also gonna re-read this: The Hologenome Concept: Helpful or Hollow? journals.plos.org/plosbiology/...

Holes in the Hologenome: Why Host-Microbe Symbioses Are Not Holobionts | mBio ABSTRACT The advent of relatively inexpensive tools for characterizing microbial communities has led to an explosion of research exploring the diversity, ecology, and evolution of microbe-host systems...

Re-reading this journals.asm.org/doi/10.1128/... “Holes in the Hologenome: Why Host-Microbe Symbioses Are Not Holobionts” and agreeing with a lot of it

Maintaining my view that the “holobiont” is a useful descriptive word, but kinda useless for informing ecological and evolutionary predictions or phenomenon outside of what coevolution and multi level selection theory already provide