We suspect that the very elevated mutation rate of L. acidophilus is influenced by its domestication status - we observe many losses of DNA repair genes across the species. Thus, the mutation rates of L. acidophilus may be actively evolving and an ideal species for studying mutation rate evolution.

We found that LAB, and L. Acidophilus in particular, have very high mutation rates.
Mutations are quite biased towards G:C ➡️ A:T and A:T➡️G:C; and this is very apparent in L. acidophilus near the ori.

Beautiful morning in the Smokies at SEPEEG 2025. Listening to Fisher’s geometric model, with coffee, in the mountain air, just hits different. 🏔️ ☕️

Our lab is hiring!!
We are looking for a research assistant who will be involved with our experimental evolution studies on how stress affects population dynamics in E. coli.
Great opportunity for recent grads!
E-mail for more info and apply here:
ecsr.fa.us2.oraclecloud.com/hcmUI/Candid...

Really proud of PhD Candidate Carl Stone, advocating for science and scientific funding by wiring this opinion piece for his hometown newspaper in Minnesota.

Really enjoyed visiting NC State for the Genetics and Genomics seminar yesterday! Got to chat with a great group of researchers, heard awesome science, and the food scene in Raleigh was pretty yum! 🧬🧫

Introducing our lab’s newest Ph.D candidate William McLaughlin. William is doing an awesome microbial systems ecology project that’s already turning out some cool results. Keep an eye out for this rising star.

There is of course more to our story so you will need to read the paper!
www.pnas.org/doi/full/10....

We also found the Arg -> His (Rho R109H) substitution in nature! Particularly in species that often navigate pH fluctuations like insect gut -> human blood or sponge microbiome-> ocean.
A great example of how lab evolution can provide insight into the natural world!

Next we collaborated with @bpbratton and found that the Rho/YdcI double mutant maintains an elevated intracellular pH, which should minimize the plasticity in mutant Rho function and maintain Rho in its alternate state that’s observed in higher pH!

We then saw that every Rho mutation arose concurrently with or following a loss/disruption of function mutation in YdcI, a poorly characterized transcription factor thought to be involved with pH homeostasis.
(These substitutions helped us get a better candidate YdcI structure)

Collaborating with @MarcBoudvillain, we found that this substitution confers pH sensitive Rho activity in vitro.

Genomic analysis of E. Coli cultures evolved for 900 days in extreme feast/famine conditions revealed that 7/16 populations acquired a mutation in the Rho transcription terminator. The most common of which conferred Arg -> His at residue 109.

🚨This week in @PNASNews 🚨
Our new paper led by postdoc @sb_worthan examining a pH sensitive substitution in the Rho transcription terminator that evolved experimentally in our lab and then is found in natural populations! Thread below! 🧵
www.pnas.org/doi/full/10....

Had a great time last night watching @NashvilleSC win with the Vanderbilt Mathematics Department.
Thanks for letting this biologist join, there’s no better way to watch a game than in the VU box! ⚽️⚓️🧑‍🏫

This new work out today in @currentbiology.bsky.social is part of our ongoing collab w/ Wei-Chin Ho!

If you are at #TAGC24, Poster #777🎰 covers this & our follow up work on pH sensing mutations in transcription termination!

Preprint Alert! 🚨🚨🚨
Exciting collaboration between my group, @MarcBoudvillain’s group and @bpbratton!

From populations experimentally evolved to extreme feast/famine cycles, we find pH-sensing rho alleles that confer pH-dependent plasticity in transcription termination!

6mA levels vary across the MG1655 genome, are decreased at the -35 site, and are reduced genome-wide in E. coli that evolved with MMR disabled (which is cool because in E. coli MMR is guided by 6mA!)

journals.asm.org/doi/10.1128/...