The paper we just published is a collaboration of 12 labs spread across 7 countries, covering sea squirt (shown here), sea urchin, beetle, crustacean, roundworm, ragworm, flatworm, jellyfish, sea anemone & choanoflagellate. Comparing the results identified tags that work well across many species 7/9
This fits the general principle of ZGA being triggered by a 'universal' Genome: Cytoplasm ratio across animals! - and thus a highly conserved mechanism involving titration of a maternal cytoplasmic factor on chromatin.
So, by providing staged embryo mRNA for this beautiful wide comparative study, we now know that zygotic gene activation in Clytia occurs in the early blastula with 512 cells, at around 5hpf (Here termed ZGA cell cycle 9).
Finding molecular tags that localise fluorescent proteins to the cell membrane was the goal of our latest paper, now published in Development @dev-journal.bsky.social. The tags act as address labels, sending proteins to the cell membrane, where they highlight the shape and arrangement of cells. 2/9
These images show live embryos of animals (jellyfish, crustacean, worm, sea urchin, sea squirt, beetle) and one of animals closest single-celled relatives. They were captured taking advantage of fluorescent proteins localised on the outer membrane of cells, allowing us to observe cell outlines. 1/9
Only 1 weeks to apply (April 7) for the joint Master program on "Evolutionary Genomics and Systems Biology" in Vienna.
studieren.univie.ac.at/en/admission...
Cool program with hands-on experience taught by leading scientists in PopGen, EvoDevo, Evolutionary Systems Biology.
Spread it!
Happy #FluorescenceFriday all!
Checkout these beautiful basal bodies in airway #multiciliated cells expanded via U-ExM 😍
Images captured by the super talented @maneesha07.bsky.social on a #Nikon NSPARC 🔬.
More fascinating jellyfish research from Noriyo Takeda, Ryusaku Deguchi and colleagues: A lovely example of speciation in action, as populations of Cladonema pacificum withmorning and evening spawning become reproductively separated. bioone.org/journals/zoo...
bioone.org/journals/zoo...
Great work, Anna!
I’m beyond excited to see our work published in Science Advances! 🎉
Deeply grateful to everyone involved — and especially to @pawelburkhardt.bsky.social for the great mentorship ✨
www.science.org/doi/10.1126/...
I'm thrilled to be co-teaching this wonderful course again this fall. Come join us at the MBL for a transformative experience!
In @eLife: Neural connectome of the ctenophore statocyst https://doi.org/10.7554/eLife.108420
Version of record of our ctenophore nerve-net connectome paper.
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...
Two funded PhD positions investigating the evolution of sarcomeres @ibdm.bsky.social in @biancah0406.bsky.social and our lab, together with @cnidevo.bsky.social - Interested to explore how similar or different Jellyfish sarcomeres are to Drosophila or human ones?
www.ibdm.univ-amu.fr/ibdm_job/2-a...
Clytia sp. IZ-D, a newly identifed jellyfish species from Izushima Island, on the Pacific coast of Japan. Life-cycle diagram (top left) and images of each stage (top ight; a–f) of Clytia sp. IZ-D, which is morphologically very similar to the model species Clytia hemisphaerica. Magenta arrows in the gonozoid cartoon (c) indicate individual medusa buds. Arrows in the mature female medusa photo (e) point to the four gonads in the subumbrella. Bottom: Illustration of spawning regulation in Clytia sp. IZ-D. This species spawns every evening, unlike the closely related C. hemispharica, which spawns in the morning. Surprisingly, in both cases, it is sunrise, not sunset, that provides the temporal cue for spawning. In Clytia sp. IZ-D at 21°C, spawning occurs 14 hours after sunrise, regardless of sunset timing. A further surprise is that a 20-hour spawning rhythm is maintained even under constant light. Such autonomous circadian gamete release has not previously been reported in cnidarians (jellyfish, corals, or sea anemones). Future molecular studies using this Clytia species are expected to shed light on the mechanisms underlying light-controlled reproduction in marine organisms. Illustration by Ruka Kitsui.
#Jellyfish rely on light cues to help time their #gamete release. @momotsuyo.bsky.social &co reveal an additional autonomous #circadian mechanism that synchronizes gamete release, entrained to a 24-hr period by dark-to-light transition @plosbiology.org 🧪 plos.io/4btAwpY
Rhythmic ovulation in Clytia species. Top row: In Clytia hemisphaerica, the oocytes develop (blue arrow) becoming competent to respond to the maturation-inducing hormone (MIH), which triggers meiosis. MIH (red triangle) is released by neurosecretory cells in the gonads when they become exposed to light. After completion of meiosis (about 2 hours), the mature eggs are released. Ovulation (green square) lasts about 10 min. Since light is required to start a cycle, whose duration is regulated by the developmental programme, in C. hemisphaerica rhythmic ovulation is analogous to an hourglass. Bottom row: In Clytia sp.IZ-D light is required for synchronous development of the oocytes (blue arrow). However, the final maturation process, which makes them responsive to MIH, is gated by an unknown mechanism that likely operates individually in each oocyte (black-and-blue arrow). Light also drives the accumulation and progressive release of MIH. Meiosis begins when the oocytes reach the right maturation stage and MIH the right concentration. After about 2 hours ovulation begins, lasting about 60 min (green box). Together, the timing mechanisms controlling oocyte development and MIH release constitute an incipient clock. Two light-dark cycles are shown for reference.
In hydrozoan #jellyfish, the timing of gamete release is often coordinated by light. Ezio Rosato explores a @plosbiology.org study that elucidates a novel, endogenous clock-based mechanism that governs #egg release in a new species of jellyfish 🧪 Paper: plos.io/4btAwpY Primer: plos.io/49eTOya
Now out in PLOS Biology- a novel clock mechanism regulating spawining in a newly-identified Clytia species
: dx.plos.org/10.1371/jour...
Happy New Year Marie-Emilie !
Happy 2026!
As usual now, jellyfish in Paris @clytia-vlfr.bsky.social
We've updated our Hydractinia Genome Project Portal! The site includes genomic, transcriptomic, and proteomic datasets, genome browsers, an interactive single-cell gene expression atlas, proteome-scale structure predictions, a custom BLAST interface, and more. Check it out! tinyurl.com/hydractinia
Come and do a PhD on 'Genome duplication, extinction and diversification in the evolution of flowering plants' with myself @jameswclark.bsky.social and Ilia Leitch @bristolpalaeo.bsky.social and join the @wgdip.bsky.social studying rediploidisation. Apply: tinyurl.com/26pmfvvc by Jan 8
Separation of the Early gastrula into oral and aboral halves shows that some neural cell tupes derive from aboral ectoderm, and others from i-cells
Drawing together findings from several projects over many years, we make a case that neural cell types in the Clytia larva have two embryological origins: i-cells and ectodermal.
bioRxiv 2025.11.17.688882; doi: doi.org/10.1101/2025...
Apply to join us! 🪼🪳🪱🐌
Tested in Clytia too - by @sassaf.bsky.social and @momotsuyo.bsky.social !
Is the deuterostome clade an artifact???
New paper with first author @anaserrasilva.bsky.social, Laura Piovani, Paschalis Natsidis and project co-led by Paschalia Kapli.
www.sciencedirect.com/science/arti...
Bravo @juliarmateu.bsky.social et @annaferraioli.bsky.social, merci à Richard Copley pour ce travail co-dirigée, et merci aux collaboratrices coralistes Isabelle Domart-Coulon (MNHN, Paris) et Núria Teixidó (LOV, et Ischia Marine Center, Stazione Zoologica Anton Dohrn)
