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Max Heiman

@heiman.bsky.social

1.1K followers 250 following 250 posts

Associate Professor of Genetics Harvard Medical School, Boston Children's Hospital It should be fun, or what's the point? http://heimanlab.com

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Max Heiman @heiman.bsky.social · 1d

No, we test our problem sets and exams on ChatGPT and it does badly. Some students come in with a strong genetics background and prefer to figure things out on their own. I would like them to be in class, but in the end, our goal is for them to learn genetics, however they get there.

Max Heiman @heiman.bsky.social · 1d

I don't know the college side. But in our grad genetics (~70 students), it's all blackboard lecture, no published recordings or notes, and sometimes there are students who never come to class or section but ace the problem sets and exams. What can you do? We have a reputation as the hardest class.

Max Heiman @heiman.bsky.social · 4d

10.
Alone in the dark
you are the first person ever
to know this new thing.

Max Heiman @heiman.bsky.social · 4d

9.
Congratulations
on scoring fifth percentile!
It won't be funded.

Max Heiman @heiman.bsky.social · 4d

8.
If the centrifuge
makes a high-pitched buzzing noise
just whack it right here.

Max Heiman @heiman.bsky.social · 4d

7.
Analysis was
rigorously performed by
ChatGPT-5.

Max Heiman @heiman.bsky.social · 4d

6.
Respected Doctor,
Shortfall of one article
for our next issue.

Max Heiman @heiman.bsky.social · 4d

5.
One microliter
at the bottom of the tube?
Back in the freezer.

Max Heiman @heiman.bsky.social · 4d

4.
The manuscript was
immensely improved by their
insightful comments.

Max Heiman @heiman.bsky.social · 4d

3.
Greetings of the day!
I hope this mail finds you well
in these troubling times.

Max Heiman @heiman.bsky.social · 4d

2.
I don't think that I
mixed up the lanes while loading
but it's possible.

Max Heiman @heiman.bsky.social · 4d

Saturday morning, waiting for kid's soccer game, is a great time to indulge in the lowest form of humor:

LAB HAIKU!

1.
Does anyone know
whose PCR is in there?
BEEP. BEEP. BEEP. BEEP. BEEP.

Reposted by Max Heiman

Priti Agarwal @pritiagarwal.bsky.social · 5d

🚨 New preprint!
We profile the transcriptome of the C. elegans distal tip cell: a persistent leader cell that invades basement membrane to shape the gonad.

Our dataset defines the molecular signature of invasive leader cells & uncovers new regulators of collective cell invasion.

Stage-specific transcriptomics of a leader cell reveals cell machineries driving collective invasion

Collective cell invasion underlies organ development, epithelial repair, and cancer metastasis. Leader cells remodel extracellular matrix, sense guidance cues, reorganize their cytoskeleton, and coord...

www.biorxiv.org

Max Heiman @heiman.bsky.social · 11d

Cilia and aECM, what more could you want?

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

Motile cilia spin the Reissner fiber, a tensioned and anchored extracellular thread essential for body morphogenesis

The Reissner fiber (RF) is an extracellular thread composed of the glycoprotein SCO-spondin (Sspo) that forms within cerebrospinal fluid (CSF) in the brain ventricles and central canal (CC) of vertebr...

www.biorxiv.org

Reposted by Max Heiman

Bruce Hamilton @bahome.bsky.social · 13d

Thomas Hunt Morgan, born 159 years ago #OTD in 1866.
Happy 1.59 centiMorgans.

en.m.wikipedia.org/wiki/Thomas_...

Thomas Hunt Morgan - Wikipedia

en.m.wikipedia.org

Max Heiman @heiman.bsky.social · 15d

Please join us!

sundaramlab.com/blog/aecm-cl...

Reposted by Max Heiman

Meera Sundaram @meera-sundaram.bsky.social · 15d

The 2025-2026 #aECM club schedule is now posted on our website, where you can also find the link to sign up for access. I’m looking forward to lots of great talks and discussions! sundaramlab.com/blog/aecm-cl...

aECM Club Seminars

A virtual seminar series to highlight work on apical ECM across different systems Organizers: Meera Sundaram, UPennMax Heiman, Boston Children’s, Harvard U.Nathalie Pujol, U. Aix MarseilleJor…

sundaramlab.com

Max Heiman @heiman.bsky.social · 19d

Will today's digital lab notebooks feel like this in 30 years?

callista yee @csybio.bsky.social · 19d

I am ready for the apocalypse, got my sequence of pPD95.75 and others right here #celegans

floppy disk of fire lab vector sequences

Max Heiman @heiman.bsky.social · 28d

well deserved, congratulations!

Max Heiman @heiman.bsky.social · Sep 7

Thank you! You are fast!

By the way, your hocking about best practices with alt-text was very much in mind as I posted all this.

Max Heiman @heiman.bsky.social · Sep 7

Importantly, the methods we developed to identify oscillatory expression are not specific to the C. elegans larval cycle.

We hope that they will allow statistically rigorous de novo identification of oscillatory genes and cell types in any system, using only broadly-timed scRNA-Seq data.

Max Heiman @heiman.bsky.social · Sep 7

Finally, we used regulatory network analysis to find transcription factors (TFs) with targets enriched among pulsatile genes.

We found some old friends that are known to control larval timing, like blmp-1, nhr-23, and nhr-25, as well as new suspects who might merit further investigation!

Plots showing enrichment scores for TFs as putative regulators of oscillatory gene expression in each cell type, based on representation of their target genes among the pulsatile genes in that cell type. Six cell types are shown (four glia, two skin) and most of them include blmp-1, nhr-23, and nhr-25 among enriched TFs.

Max Heiman @heiman.bsky.social · Sep 7

This implies that the cuticle is not a homogeneous mesh at all, but a patchwork that is stitched together from totally different, cell-type-specific components.

Japanese patchwork vest from the early 1800s, from the Metropolitan Museum.

Max Heiman @heiman.bsky.social · Sep 7

But a surprise to me was how little overlap there was between cell types. For example, although many cells are making collagens, they're making DIFFERENT collagens. Same with most genes.

In fact, almost half the pulsatile genes we identified were oscillatory in only a single cell type!

Plot showing how many genes are expressed in a pulsatile manner in one, two, three, etc. different cell types. Over 2000 genes are pulsatile in only a single cell type; a little over 1000 genes in only two cell types; and fewer and fewer are pulsatile in multiple cell types.

Max Heiman @heiman.bsky.social · Sep 7

Using these new tools, we could ask what kinds of genes oscillate in glia, or skin, or pharynx. For glia and skin it turns out it's mostly #aECM - lots of collagens, ZP domain proteins, and other cuticle proteins. Pharynx has a different kind of cuticle and its oscillatory genes reflect that.

Plots showing how many collagens, ZP domain proteins, or other ECM families are expressed in a pulsatile manner in each cell type.