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Lior Pachter

@lpachter.bsky.social
10K followers 871 following 229 posts

Bren Professor of Computational Biology @Caltech.edu. Blog at liorpachter.wordpress.com. Posts represent my views, not my employer's. #methodsmatter

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Reposted by Lior Pachter
Auschwitz Memorial @auschwitzmemorial.bsky.social · 22/09/2026
22 September 1939 | Dutch Jewish boy, Abraham de Leeuve, was born in Zwolle. He was deported to #Auschwitz from Westerbork on 19 Oct 1942. He was murdered in a gas chamber after the selection with his mother, Dina. --- VIDEO: The first two gas chambers near Birkenau: youtu.be/Rr6lF75fDmU
Vintage black-and-white family portrait featuring a child flanked by a man and a woman. The child is in the center wearing a patterned sweater.
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Richard Sever @richardsever.bsky.social · 30/08/2026
‘Unrefereed, unindexed and unread’ was the joke I always made about supp data. AI will change that… (Via @lpachter.bsky.social )
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Lior Pachter @lpachter.bsky.social · 05/08/2026
Proof of the 40-year old Bandelt-Dress conjecture on the maximum quartet distance between phylogenetic trees (and an interesting connection to independence testing). arxiv.org/abs/2608.03542
arxiv.org
The maximum quartet distance between phylogenetic trees
The quartet distance counts the four-leaf subsets on which two binary phylogenetic trees display different topologies. We prove that its maximum over trees on $n$ leaves is $(2/3+o(1))\binom{n}{4}$, r...
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Lior Pachter @lpachter.bsky.social · 30/07/2026
One of the major pains of academia is having to click through labyrinths of webpages to submit papers. Now, thanks to Joe Rich (and AI), problem solved! His tool is called PaperPush and is available at github.com/pachterlab/p... It's super easy to use! 1/🧵
github.com
GitHub - pachterlab/paperpush
Contribute to pachterlab/paperpush development by creating an account on GitHub.
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Lior Pachter @lpachter.bsky.social · 26/06/2026
Efficient sampling of reads (with replacement). www.biorxiv.org/content/10.6...
biorxiv.org
fastQpick: scalable bootstrap and subsampling of FASTQ reads
fastQpick is a command-line tool and Python library for sampling FASTQ reads with replacement. Sampling with replacement turns a single FASTQ file into an arbitrary number of bootstrap replicates, whi...
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Yasin Dagdas @plantophagy.bsky.social · 26/06/2026
I wonder what @elife.bsky.social board and behrenstimb.bsky.social thinks about the 1% list and their coll/ with @qedscience.bsky.social now? They’re facilitating the innovation of a system that will be bought by #Elsevier & #Springer w/funds from a charity.
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Reese Richardson @reeserichardson.bsky.social · 28/05/2026
TL;DR: We've identified more than 100 cases of apparent manipulation in Thermo Fisher Scientific's antibody verification data. @sholtodavid.bsky.social @johanduchene.bsky.social reeserichardson.blog/2026/05/28/h...
reeserichardson.blog
How much of Thermo Fisher’s antibody data has been manipulated?
We’ve documented more than 100 instances of apparent data manipulation in Thermo’s catalog
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Lior Pachter @lpachter.bsky.social · 26/05/2026
lake is amazing
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Lior Pachter @lpachter.bsky.social · 13/05/2026
Indeed, #methodsmatter www.nature.com/articles/s41...
nature.com
Package selection and versioning matter - Nature Methods
Nature Methods - Package selection and versioning matter
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William DeWitt @wsdewitt.github.io · 29/04/2026
Arc Institute’s “MULTI-evolve” learns a classical additive model, not epistasis. Preprint (w/ Gian Marco Visani and Aayush Verma): www.biorxiv.org/content/10.6... Blog: dewitt-lab.github.io/posts/2026-0...
dewitt-lab.github.io
Additivity is all you need?
Arc Institute’s “MULTI-evolve” learns a classical additive model, not epistasis.
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Lior Pachter @lpachter.bsky.social · 04/05/2026
Vito Volterra (of the Lotka-Volterra model) was born on this day (May 3rd) in 1860. Volterra was in the 1%. That is, he was one of only 12 out of ~1,200 Italian professors who refused to sign the compulsory oath of allegiance to Mussolini's Fascist government in 1931.
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Lior Pachter @lpachter.bsky.social · 14/04/2026
Hausdorff. liorpachter.wordpress.com/2026/04/14/h...
liorpachter.wordpress.com
Hausdorff
The philosopher Felix Hausdorff, famous for his foundational philosophical work Das Chaos in kosmischer Auslese  (Chaos in Cosmic Selection) in which he rejects metaphysics, also did mathematics as…
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Isabel @isabelott.bsky.social · 13/04/2026
Behind every extrernally lauded ‘disruptor’, there seems to be a half dozen (minimum) actual subject matter experts shaking their heads “no” and grimacing dramatically. Good to keep in mind, for those of us prone to a bit of epistemic…moseying.
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Lior Pachter @lpachter.bsky.social · 13/04/2026
If you use dim. reduction, you may be interested in two recent preprints we've posted on contrastive PCA: The Rayleigh Quotient and Contrastive Principal Component Analysis I & II w/ Maria Carilli & Kayla Jackson. They cover a lot of ground from theory to practice. 1/🧵
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Rowena Ball @rowena-mathscieng.bsky.social · 12/04/2026
Some people seem quite fond of finding third fundamental principles. They get fixated on their new third law of thermodynamics or of evolution. Perhaps there is a third law of misunderstanding.
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Lior Pachter @lpachter.bsky.social · 11/04/2026
On Martin Nowak, the evolution of cooperation, Jeffrey Epstein, and the corruption of mathematicians. liorpachter.wordpress.com/2026/04/10/n...
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Lior Pachter @lpachter.bsky.social · 11/04/2026
I don't understand rewrites.bio at all. Most bioinformatics software is distributed with a license. The license specifies exactly what is and is not permitted to do with the software. Yet now one is supposed to ignore the license and adhere to requirements specified by someone on a website??
rewrites.bio
rewrites.bio - A manifesto for bioinformatics
Principles for responsible AI-assisted rewriting of bioinformatics tools.
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bioRxiv Evolutionary Biology @biorxiv-evobio.bsky.social · 10/04/2026
Spectral requirements for cooperation www.biorxiv.org/content/10.64898/20…
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Will Ratcliff @wcratcliff.bsky.social · 07/04/2026
1/25 New paper out in PNAS! We show that the fitness costs of reproductive specialization, where somatic cells give up reproduction, scale inversely with organism size. Larger organisms can afford far more soma, removing a key barrier to multicellular complexity.
pnas.org
The fitness costs of reproductive specialization scale inversely with organismal size
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Lior Pachter @lpachter.bsky.social · 07/04/2026
Happy to see multiple optimizations to the edgePython codebase, with more on the way: github.com/pachterlab/e... I have already experimented with porting to Rust, and have it mostly done (with some extra speedup); useful to complete an end-to-end single-cell Rust ecosystem.
github.com
GitHub - pachterlab/edgePython: Repository for edgePython which is a Python implementation of the Bioconductor edgeR package for differential analysis of genomics count data.
Repository for edgePython which is a Python implementation of the Bioconductor edgeR package for differential analysis of genomics count data. - pachterlab/edgePython
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Lior Pachter @lpachter.bsky.social · 06/04/2026
Interesting to see people who have spent their careers talking about how important open source is, now upset that someone has taken their MIT or BSD licensed code and ported or modified it with an LLM.
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Lior Pachter @lpachter.bsky.social · 13/03/2026
A new long-read preprint: run PIP-seq then PCR & put the library on ONT. Sadly, no data available so comparisons to other tech not possible (also scripts missing). Requires Fluent Biosciences kits (they tried to reverse engineer the PIP-seq whitelist which seems to breach the Fluent EULA).
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Lior Pachter @lpachter.bsky.social · 09/03/2026
Ambient RNA & barcode swapping is a serious issue in single-cell genomics. Tools such as CellBender, scAR, DecontX & SoupX. We have developed CellSweep which is faster (in some cases by a lot) and much more accurate. Extensively tested and benchmarked. www.biorxiv.org/content/10.6... 1/
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Lior Pachter @lpachter.bsky.social · 07/03/2026
"In the end, I started wondering if all of BioConductor could be ported to Python - or perhaps Julia or Rust for pure language implementations that also cover the optimized parts written in C, C++, or Fortran."
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Páll Melsted @pmelsted.bsky.social · 06/03/2026
Excited to share this preprint that describes my latest work on using GPUs to accelerate processing of RNA-seq data. The title says it all: "RNA-seq analysis in seconds using GPUs" now on biorxiv www.biorxiv.org/content/10.6... and github github.com/pachterlab/k... Figure 1 shows they key result
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Lior Pachter @lpachter.bsky.social · 06/03/2026
kallisto sped up RNA-seq quantification by 50x. Now another 50x speedup... quantify hundreds of millions of reads in a few seconds. This seems too good to be true. But it's true! Incredible accomplishment by @pmelsted.bsky.social.
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Gennady Gorin @goringennady.bsky.social · 03/03/2026
After years of work, the centerpiece of my PhD is published in @natmethods.nature.com! Read it to learn about the biophysical insights we can get from single-cell data! But first, I would like to talk a bit about RNA velocity and normalization. 1/
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Cnidarian developmental mechanisms group @clytia-vlfr.bsky.social · 18/02/2026
Introducing a Clytia planula cell atlas, and demonstrating broad-level relations with medusa cells via another updated atlas. By @annaferraioli.bsky.social with @juliarmateu.bsky.social and collaborators in a project led by @rcply.bsky.social @biodev-vlfr.bsky.social www.biorxiv.org/content/10.6...
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Michel Nivard @michelnivard.bsky.social · 19/02/2026
years ago my student and I translated LD score regression form Python to R, it took months, and LDscore at the time was like 3/4 reasonably functions! Translating EdgeR to Python in a week is absolutely crazy…
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Michel Nivard @michelnivard.bsky.social · 19/02/2026
got curious, codex translated the core features of LD score regression from python to R in under an hour... Obv not a whole package but enough to see you'd soon be able to flick things between Python and R as it suits you...
github.com
GitHub - MichelNivard/ldsc-r-codex-translation
Contribute to MichelNivard/ldsc-r-codex-translation development by creating an account on GitHub.
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Lior Pachter @lpachter.bsky.social · 19/02/2026
On April 24, 2026 a new rule kicks in whereby state and local governments will require WCAG 2.1 Level AA for web content. The PDF for the preprint describing this project is UA-2 which is a "gold standard" for PDF accessibility. I built it using luatex in combination with verapdf and LLM assistance.
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Lior Pachter @lpachter.bsky.social · 19/02/2026
This MCP server for edgePython should be useful for anyone building (comp)bio agents: github.com/pachterlab/e...
github.com
GitHub - pachterlab/edgePython: edgePython is a Python implementation of the Bioconductor edgeR package for differential analysis of genomics count data. It also includes a new single-cell differentia...
edgePython is a Python implementation of the Bioconductor edgeR package for differential analysis of genomics count data. It also includes a new single-cell differential expression method that exte...
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Lior Pachter @lpachter.bsky.social · 19/02/2026
I used Claude Opus 4.5/4.6 (and a bit of Codex GPT-5.3) to port edgeR to Python. See edgePython github.com/pachterlab/e... This allowed me to develop a single-cell DE method that extends NEBULA with edgeR Empirical Bayes. All in one week. Details in doi.org/10.64898/202...
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Lior Pachter @lpachter.bsky.social · 19/02/2026
Cool new paper on how to think about aggregation for spatial transcriptomics by Lambda Moses et al. www.biorxiv.org/content/10.6...
biorxiv.org
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Lior Pachter @lpachter.bsky.social · 18/02/2026
media.tenor.com
patrick star from spongebob squarepants is smiling with his hands folded
ALT: patrick star from spongebob squarepants is smiling with his hands folded
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Mark Peifer (He, him) @peiferlabunc.bsky.social · 15/02/2026
I unfortunately have a different story. I served on a hiring committee which initially failed. A late candidate then emerged with a superb publication record. There were reports of sexual misbehavior as a PhD student circulating but they were now married with kids. I voted yes 1/n
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Lior Pachter @lpachter.bsky.social · 11/02/2026
Interesting article on LLM text extraction and the connection of that problem to (computational biology) sequence alignment. www.biorxiv.org/content/10.6... by @sina.bio and Aaron Streets.
biorxiv.org
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Lior Pachter @lpachter.bsky.social · 03/02/2026
AI hallucinations in science manuscripts are a nuisance. Paranormal citations, or paracites, will be a nightmare. www.biorxiv.org/content/10.6... (w/ @sina.bio & @lauraluebbert.com).
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sina b @sina.bio · 03/02/2026
Peer review is often opaque and confusing. @elife.bsky.social worked to change that. In a new preprint, we show how eLife’s Publish, Review, Curate model makes it possible to evaluate AI-generated reviews (with OpenEval) against human peer review. w/ @lauraluebbert.com and @lpachter.bsky.social
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Alex Merz 🇺🇸🇨🇦🇺🇦 @merz.bsky.social · 01/02/2026
Watson. Of course.
Epstein files search returns 109 entries for string "James Watson"
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Shira Weingarten-Gabbay @shiraweingarten.bsky.social · 28/01/2026
Join us tomorrow at the #SystemsVirologyJournalClub. @lauraluebbert.com will present her work with @lpachter.bsky.social on detecting viruses at single-cell resolution and uncovering associated changes in host gene expression. Paper: pubmed.ncbi.nlm.nih.gov/40263451/
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Nature Biotechnology @natbiotech.nature.com · 16/01/2026
The January issue is live nature.com/nbt/volumes/44 /issues/1 On the cover, Luebbert et al. present a method to detect viral sequences in bulk and single-cell transcriptomic data using conserved amino acid domains instead of annotated reference genomes go.nature.com/4lGrSY3
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Marc Robinson-Rechavi @marcrr.bsky.social · 15/01/2026
First I'm hearing of DOPRA, love it! "Denial of peer review attack" concept by @lpachter.bsky.social
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Lior Pachter @lpachter.bsky.social · 26/12/2025
I highly recommend reading @harveylederman.bsky.social's essay on the meaning of life, the universe, and everything as you ponder the end of 2025, and other things that may soon end as well... scottaaronson.blog?p=9030
scottaaronson.blog
ChatGPT and the Meaning of Life: Guest Post by Harvey Lederman
Scott Aaronson’s Brief Foreword: Harvey Lederman is a distinguished analytic philosopher who moved from Princeton to UT Austin a few years ago. Since his arrival, he’s become one of my …
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Darren Dahly @statsepi.bsky.social · 17/12/2025
That is what a Denial of Peer-Review Attack looks like (DOPRA: credit to @lpachter.bsky.social for the term) x.com/lpachter/sta...
x.com
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Lior Pachter @lpachter.bsky.social · 04/12/2025
My student Catherine Felce will be defending her thesis @caltech.edu next week. If you're in the area consider attending; it will be a treat! Cat's recent work: journals.aps.org/pre/abstract... www.biorxiv.org/content/10.1... www.biorxiv.org/content/10.1...
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Joshua G. Schraiber @jgschraiber.bsky.social · 26/11/2025
We've got a really cool preprint out in collaboration with @lpachter.bsky.social's awesome student Cat Felce. Using biophysical models and RNA-seq data, we explore the mechanisms of selective constraint on mRNA abundance, finding constraint on decay rate www.biorxiv.org/content/10.1...
biorxiv.org
Biophysical constraints on mRNA decay rates shape macroevolutionary divergence in steady-state abundances
Evolutionary changes to gene expression are understood to be a major driver of phenotypic divergence between species. Researchers have investigated the drivers of this divergence by fitting evolutiona...
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Rosa Lafer-Sousa @rosalafersousa.bsky.social · 08/11/2025
When I was 17, I attended a seminar Watson gave about the RNA tie club and their 1954 summer in Woods Hole. During the seminar, the 76 year old shared headshots of young women he took on beach dates. He also showed lab group photos and took the time to point out the women he had harangued for dates.
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Daniel E. Weeks @statgendan.bsky.social · 08/11/2025
In 1982, I was in the Jackson Laboratory Research Training Program. As part of the program, we got to attend the Short Course lectures. At the end of one lecture by a young researcher, this old guy very viciously and aggressively lit into him. Turned out that the nasty old guy was Jim Watson.
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