Joanna Masel

@joannamasel.bsky.social

Theoretical biologist and advisor to data scientists at the University of Arizona. Mostly theoretical population genetics and molecular evolution, but I've also published in biochemistry, infectious disease, aging, economics, education. Opinions are my own

What do the earliest organisms tell us about where life began on earth? This fantastic paper addresses this issue through analyses that expose early metabolism, & what the environment contributed to kick start it. Even if wrong it is worth reading for the clear introduction to metabolism.

Intermediate stages in the origin of metabolism at a phosphorylating hydrothermal vent

Enzymatic metabolism emerged from metal-catalyzed, aqueous reactions of H2, CO2, NH3 and phosphite at a hydrothermal vent.

science.org

The most anti-legal immigrant administration ever just made it illegal for international students to transfer schools or change majors or shift any "educational objective" in their 1st year and for graduate students **at any point** ever, at all. There is no legal basis for this

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#SMBE #SMBE2026 Public Service announcement: If you want people to be able to find you in the app: (1) Click on the 'menu' lines (top right), (2) then click on "Privacy & Settings" and (3) *then* scroll to the bottom and click 'update'. This was not obvious to me.

So the #SMBE2026 conference app seems pretty unusable. You can only star whole sessions not individual talks, and you can't see which talks are on at the same time. Before I burn CO2 feeding it to an AI agent to produce a usable spreadsheet, does anyone already have one?

Calling all Scientists! Research Administrators! Deans! Fans of Science! No one is coming to save us. Here is your assignment. I have written a step by step, easy to understand "how-to" document to help you comment on the proposed OMB rule. elizabethginexi.substack.com/p/what-we-ne...

What We Need to do NEXT: OMB’s Proposed Federal Financial Assistance Rule (OMB 2026-10817)

What OMB’s Proposed Federal Financial Assistance Rule Means in Practice

elizabethginexi.substack.com

1/ Our new paper in Systematic Biology "Modeling Site-and-Branch-Heterogeneity with GFmix" led by @cgpmcc.bsky.social describes improved ways to model compositional heterogeneity across both sites and branches—an important source of error in deep phylogenomics. doi.org/10.1093/sysb...

Modeling Site-and-Branch-Heterogeneity with GFmix

Abstract. Phylogenetic trees are often inferred from protein sequences sampled from diverse taxa across the tree of life. The compositions of these amino a

doi.org

One glimmer of hope in the Ebola response: Within hours of the outbreak in DRC being declared, researchers convened to prepare drug trials. A lot has changed on that front since the Ebola outbreak in West Africa a decade ago. But huge challenges remain 🧪 My story in @science.org (🧵 to come)

Can fast, nimble clinical trials deliver a drug to halt the new Ebola outbreak?

Past outbreaks spawned clever strategies for testing antivirals and antibodies, but researchers will still face major challenges on the ground

science.org

Our paper unpacking "fitness" is out doi.org/10.1093/gene.... How to define fitness depends on what question you ask. Selection acts on organismal vital rates, longer-term outcomes make sense for genetic lineages, models link them. "Invasion fitness" = speed, but sometimes probability matters more.

Why there are so many definitions of fitness in models

Abstract. Evolutionary “fitness” is operationalized in many different ways in models. Its role is to quantify that which is favored by natural selection. G

doi.org

Joanna Masel@joannamasel.bsky.social · 2y ago

Our latest preprint doi.org/10.32942/X2V... explains why fitness can be defined in so many ways, and which version(s) you should use when. Fitness quantifies what natural selection favors. 1/

We (with @dornhaus.bsky.social) finally wrote up our class on how to teach modeling to biologists, which ends up being a non-trivial exercise in understanding the roles that theory plays in the scientific method. We hope others will use our class, or simply enjoy the manuscript!

Anna Dornhaus@dornhaus.bsky.social · 5mo ago

Preprint: What good is modeling? Introducing biology students to theory - arxiv.org/abs/2604.13344 - how to teach and think about what modeling contributes to science. How does it fit into the scientific method? This is often misunderstood.

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

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New paper out! Here's a puzzle: phototrophy, the ability to use light for energy, is one of life's great innovations. It evolved early and transformed the biosphere. But it evolved 2x. Why not just once, why not more? Our work suggests the answer is priority effects. www.nature.com/articles/s44...

Priority effects inhibit the repeated evolution of phototrophy - npj Complexity

npj Complexity - Priority effects inhibit the repeated evolution of phototrophy

nature.com

New and Competitive renewals These are still be made VERY slowly. Only 75 awards have been made through 1/23/26. These are now from 7 institutes and centers (NIA (45), NINDS (16), NIDDK (5), NIDCR (4), NIDCD (2), NHLBI (1), and NCATS (1)). 3/3

A line graph of the number of NIH awards for new and competitive renewal grants made in fiscal year 2026 compared to fiscal years 2021 through 2025. The curve for fiscal year 2026 appears to be essentially at zero on this scale.