Mark Bitter

I am seeking a postdoc to join my group at UCLA -- ideally the candidate would have some experience in either population genetics or microbes/microbiome (computational background needed). We have a range of projects and are happy to tailer to your interests. Please dm/email me if interested.

Lab morale got you down? Try a handbook Documents that lay out a research group’s ethos and practical guidelines are becoming increasingly popular in the academic community.

Scientists across the career spectrum are burnt out, & people are leaving STEM in startling numbers, particularly those from under-represented groups. A lab handbook can foster a more positive research culture. By @scattercushion.bsky.social @nature.com 🧪 www.nature.com/articles/d41...

Very excited to be going to the Annual Drosophila Research Conference @genetics-gsa.bsky.social in Chicago this March. I think #Dros26 is the hashtag. There is still time for you to register! The fly community is so welcoming and supportive—if you are new to flies please consider going.

Excellent piece by Matz @heatshok.bsky.social and colleagues discussing the dire status of Caribbean reefs, and potential plans and policies that can be implemented if these reefs are to have any chance. Check it out in PNAS!

Registration is open for the inaugural GRC conference in the Function of Evolving Systems. Aug 9-14, 2026, Waterville Valley. Truly stellar speaker lineup. Student/postdoc fellowships are available! Please come join us! www.grc.org/function-of-... @joybergelson.bsky.social

How does the strength of genetic drift evolve over long times?

New preprint out 👇

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

SpaceBar enables single-cell-resolution clone tracing with imaging-based spatial transcriptomics Nature Methods - SpaceBar is a cellular barcoding strategy for simultaneous analysis of cell clonal and spatial identities.

Excited that SpaceBar is now out in Nature Methods!🥳

We combined clone tracing with spatial transcriptomics to untangle what drives gene expression in tumors: a cell's identity or its neighborhood?

Most genes were driven by location, but some showed strong clonal patterns.

rdcu.be/eVhpc

Working on this paper fundamentally changed how I thought about bacterial evolution, and I couldn't ask for a better to Hannukah present than to see it out, at last!

If you are interested in this work and are looking for a postdoc position, please get in touch -- we are actively looking for someone to join our group at UCLA!

Gene-specific selective sweeps are pervasive across human gut microbiomes - Nature Development and application of the integrated linkage disequilibrium score (iLDS) reveals both selective pressures impacting the human gut microbiome and the mechanisms by which gut bacteria adapt to ...

Grateful to share our paper on gene-specific selective sweeps in human gut microbiomes, now out in Nature! It has been a joy to work with @rwolff.bsky.social, whose insights and hard work made this possible.
www.nature.com/articles/s41...

So excited to share this work led by @alexrob.bsky.social with Ben Kerr!

We investigated a poliovirus capsid inhibitor that exploits a breakdown in the genotype-phenotype map to prevent drug resistance evolution. Or does it?

See Alex's thread, but a few extras:

#socialviruses #evosky #virosky 🧪

Genuinely one of the most important and interesting papers I have been a part of! Relevant to fundamental questions regarding the predictability of adaptation, as well as the applications of genomic data. Congrats to @j-smiley-rhodes.bsky.social and all co-authors for such a masterpiece!

Super excited that the bulk of my PhD work is now preprinted! Here we used whole-community competition, or coalescence, experiments to quantify selection acting on genetically diverged strains within larger communities. (1/n)
www.biorxiv.org/content/10.1...

Massively parallel interrogation of the fitness of natural variants in ancient signaling pathways reveals pervasive local adaptation The nature of standing genetic variation remains a central debate in population genetics, with differing perspectives on whether common variants are almost always neutral as suggested by neutral and n...

One of the most exciting works of my career, years in the making. We used high-throughput precision genome editing to test the fitness effects of thousands of natural variants. Our findings challenge the long-held assumption that common variants are inconsequential.

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

One week to apply for our fully funded PhD position in Norway! This is a really exciting project in collab. with University of Helsinki and Benchmark Genetics.

Samples are ready - you do (read: learn) everything - functional genomics, bioinformatics, genotype-phenotype associations 🤩

Please RT!

Human-mediated land-use and climate change occur simultaneously, but how do they interact to shape adaptive dynamics? Super excited to share the first paper from the Kreiner lab, led by postdoc extraordinaire @rpineau.bsky.social

New preprint led by undergrad Owen Moosman! We uncover extensive haplotype diversity in antifreeze protein gene copy number in polar Zoarcoidei fishes, and report new tools to evaluate assembly uncertainty and switch error in phased genomes www.biorxiv.org/content/10.1...

Very excited to see this work in press! I think there is a reason to believe that this is a common means of stabilizing large-effect polymorphisms in general and might be an important reason for why diploidy is so common. news.stanford.edu/stories/2025...

Beneficial reversal of dominance maintains a large-effect resistance polymorphism under fluctuating insecticide selection - Nature Ecology & Evolution Measuring selection and dominance in fitness of the insecticide-resistant Ace alleles in Drosophila melanogaster, the authors show evidence for beneficial reversal of dominance, a mechanism that can s...

How do populations maintain an evolutionary memory? I am happy to share that our work with Dmitri Petrov @petrovadmitri.bsky.social, Paul Schmidt, and colleagues on dominance reversal and stabilization of insecticide resistance in changing environments over time is now published at Nature EE.

Check out our paper in Evolution Letters!

We used D. melanogaster pigmentation as a focal trait to explore parallelism in phenotypic and genomic responses to environmental change - read more at the link below 👇

I am seeking a postdoc for my group at UCLA. We work at the intersection of population genetics x microbiome (garud.eeb.ucla.edu). If interested, please message me!

Come join us at UCLA!!! We have a growing population genetics community here and Nandita and her lab are outstanding!

Junior, Assistant, or Associate Specialist – Xue Lab University of California, Irvine is hiring. Apply now!

The Xue lab at UC Irvine is looking for a staff scientist to support our work investigating how microbes interact and evolve in the gut microbiome! Open to a wide range of previous experience levels, see ad for more.
recruit.ap.uci.edu/JPF09601

We are recruiting students who are thinking of applying to Biology PhD programs this fall to apply for the Stanford Biology Preview Program. Please spread the word!

1/n 🧵 Excited to share our new paper! We developed a framework to reveal hidden simplicity in how organisms adapt to different environments, particularly focusing on antibiotic resistance evolution. #EvolutionaryBiology #MachineLearning

Increased rates of hybridization in swordtail fish are associated with water pollution Biodiversity loss can occur when disturbance compromises the reproductive barriers between species, causing them to collapse into a single population through hybridization. Recent research has documen...

1/9 Excited to share the preprint for the second half of my PhD with @mollyschumer.bsky.social: Connecting human environmental impacts to hybridization in swordtail fish through genomics, GIS, water chemistry, and histology. Thread below!

#SciSky

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

Manual validation finds only ultra-long long-read sequencing enables faithful, population-level structural variant calling in Drosophila melanogaster euchromatin The increasing accessibility of long-read sequencing and the rapid development of automated variant callers are promoting the generation of population-level structural variation data. However, the eff...

Excited to share the first manuscript from my PhD in which we leveraged ultra-long Nanopore sequencing, D. melanogaster inbred lines, and a ton of manual validation to investigate the effects of long-read length on population-level structural variant (SV) calling accuracy! doi.org/10.1101/2025...

Mixing microbiomes in vitro reveals rules of community assembly | PNAS Mixing microbiomes in vitro reveals rules of community assembly

Our commentary on the elegant in vitro microbiome coalescence experiments from @goldmandoran.bsky.social @ksxue.bsky.social et al is out.

It was a pleasure to write about one of my favorite microbiome papers of the last few years.

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

5 relative abundance plots arranged to have increasing compositional variability (variability across relative abundance samples, here vertical bars)

1/ Hey y'all, I'm excited to share my latest paper, which is out now in PNAS! We introduce FAVA, a statistical framework to measure compositional variability across microbiome samples. If you want to measure variability across a stacked bar plot, FAVA is for you! Paper: doi.org/10.1073/pnas...

Thank you for the coverage! Excited that this work, in collaboration with @markcbitter.bsky.social and many others, is now out!