Alexa Sadier

A small polymerase ribozyme that can synthesize itself and its complementary strand The emergence of a chemical system capable of self-replication and evolution is a critical event in the origin of life. RNA polymerase ribozymes can replicate RNA, but their large size and structural ...

How could a simple self-replicating system emerge at the origins of life? RNA polymerase ribozymes can replicate RNA, but existing ones are so large that their self-replication seems impossible. Could they be smaller?

Excited to share our latest work in @science.org on a new small polymerase.
1/n

scdb2026.sites.ucsc.edu. Registration is open for the Santa Cruz Developmental Biology meeting AUGUST 2026. PLEASE SHARE.

Évidemment :) sous doz avec wsl2 pour linux. Ce serait impossible de ne pas l'être étant donné ce qu'on fait en bioinfo et anat (ou alors ils auraient des tickets toutes les 5 min). Impossible de brancher des ordis perso en filaire par contre (sauf exception et après inspection uniquement)

Very last chance to join us (Deadline tomorrow Feb 10!) at this Developmental Biology meeting!
Have a nice story? Come and discuss it with editors from @embojournal.org @plosbiology.org and @dev-journal.bsky.social !
A one hour info session from @erc.europa.eu will also be presented!

Si la descente dame n'avait pas été aussi CHERE (500 balles quand j'ai regardé à l'arrache), j'y serais allée :)

Ah si moi j'ai vraiment hâte pour toutes les épreuves d'alpin (que je suis en temps normal de toute façon sur eurosport), le biathlon/fond (que je regarde de loin en temps normal), j'ai hâte de voir le skialpi, et ensuite je regarderai dans doute quelques autres sports plus confidentiel en glace

Perso beaucoup plus que ceux d'été !

Yup

Donc si vous êtes une femme scientifique et que vous êtes co-autrice d’un joli papier publié récemment, ou alors que vous avez juste vu un super papier dans votre domaine, faites-moi signe 👋

What were the first animals? The fierce sponge–jelly battle that just won’t end For almost two decades, scientists have debated whether sponges or comb jellies are the first animal lineage. Now some are calling for a more harmonious approach.

The last word on Ctenophores versus Sponges (not).
www.nature.com/articles/d41...

Situation gravissime dans les Universités : lettre de la Présidente de @univpaulvalery.bsky.social au Président Macron.

www.lemonde.fr/campus/artic...

@yannbisiou.bsky.social

Caecilians maintain a functional long-wavelength-sensitive cone opsin gene despite signatures of relaxed selection and more than 200 million years of fossoriality The colonization of low-light environments exerts selective pressure to enhance non-visual senses while relaxing selection on vision, often leading to opsi

🚨NEW PAPER 🚨 #Caecilians maintain a functional long-wavelength-sensitive cone opsin gene despite signatures of relaxed selection and more than 200 million years of fossoriality, published in Evolution @sse-evolution.bsky.social

academic.oup.com/evolut/artic...

Organizing an intensive writing day for a group of experienced & junior scientists!Goals are to outline manuscript, agree on questions/hypotheses, draft sections, start analysis.

Team will be split into outlining/writing + stats/analysis group.

Tips for max progress & momentum after?

Four camera-type eyes in the earliest vertebrates from the Cambrian Period - Nature Early vertebrates, particularly myllokunmingids, possessed four camera-type eyes (a pair of lateral eyes and pineal and parapineal organs), which indicates that these structures functio...

New paper presenting rather compelling evidence that the stem-vertebrate Haikouichthys had paired lateral and supranumerary medial eyes (!!!), and proposing that the medial eyes may have deep homology with the pineal and parapineal organs.

www.nature.com/articles/s41...

Oxygen-free metabolism in the bird inner retina supported by the pecten - Nature While the photoreceptor outer segments in the bird outer retina have access to oxygen, the inner retina operates under chronic anoxia, supported by anaerobic glycolysis in the retinal neurons.

Bird retinae are among the most oxygen-hungry tissues known, but they do their stuff entirely anaerobically, thanks to a structure called the pecten. This paper in @nature.com also contains the most antique citation I've ever seen www.nature.com/articles/s41...

Not the politicians but the people, your neighbors, friends, family. Write scicom books, press releases, show your cool work. Share the enthusiasm. Non scientists will listen :)

Stand for science, never give up because it is so important if you believe in it. And safe care when needed. I might also add my perspective from somebody who had been in the US for 9 years before coming home (France). And what I miss from the US is how much people, citizens, love science there.

Adaptive spread of a sexually selected syndrome eliminates an ancient color polymorphism in wall lizards Genetically determined color morphs are found in many animals. Polymorphism can be maintained by social selection if competitive interactions allow each morph to increase in frequency when rare. This ...

Great new study about the loss of a colour morph in Common Wall Lizards (Podarcis muralis)

www.science.org/doi/10.1126/...

Yes bitch 😆 Mais oui, c'est toujours la question, bon après je pense que de tout temps des gens ont apprivoisé des animaux sauvages, tant que ça reste marginal, ça va ^^

😂 les derniers sont pas mal

Feeding Steven Daily feedings to gain his trust. High Protein meals = healthy seagull. new merch! https://feedingsteven.com/ Contact 📬 collab@feedingsteven.com

youtube.com/@feedingstev...

An ancient genome duplication event drives the development and evolution of spinnerets in spiders A genome duplication event during the Silurian played a crucial role in the evolutionary emergence of spinnerets in spiders.

More than 400 million years ago, during the Silurian Period, an evolutionary event led to the later emergence of spiders’ spinnerets—the abdominal organs that make silk—according to new #ScienceAdvances research. https://scim.ag/4sFX3pJ

I have never been a huge fan of Nat Eco Evo (at the beginning especially) but in my field, there are nice things lately. My understanding is that people publish there for visibility (or transfer after Nat/Sci rejection).

Thankfully, a lot of male colleagues are super supportive and wonderful but I am shocked to see how some fields remain impregnated by what you describe.

Thanks so much Marie! Such an important thread. I remember a colleague telling me a few years ago "You did not experience sexism? Wait until you are a PI". She was SO true. For me it is mainly assuming I am less experienced (at 41), too young, not even mentioning how people react when standing up.

🚨 New offer in our lab:
🐝🧬22-month postdoc or engineer position to estimate the effectiveness of the genetic queen fertilisation control in honey bees through large-scale sequencing and genomic analysis
Location: Toulouse, France 😍
More information: thibaultleroyfr.github.io/pdf/Annonce_...
Reposts🙏

‘A bombshell’: doubt cast on discovery of microplastics throughout human body Exclusive: Some scientists say many detections are most likely error, with one high-profile study called a ‘joke’

"serious doubts over >50% of high impact papers [on] microplastics...brain microplastic paper is a joke...race to publish led to rushed results and routine checks overlooked" www.theguardian.com/environment/...

Why does life explore so few of the forms it could possibly take? Using fractal descriptors, this #scienceadvances paper shows that Earth’s biosphere clusters around simple shapes, reflecting deep evolutionary constraints. @artemyte.bsky.social @manlius.bsky.social www.science.org/doi/pdf/10.1...

I explained the dangers of the recent politicization of grant reviews at NIH for The Hill, and also that while diversity otherwise remains a bad word, geographic diversity is somehow laudable.
thehill.com/opinion/tech...

I am very happy (and a bit scared) to present to you what we have been working on over the last 4 years. This manuscript is exactly what I dreamt of when I started the lab and I could not be happier and prouder of the outcome!