Scanning Electron Micrographs (SEM) of a sea anemone stinging cell (F) and change in cell identity following the knockout of a gene called NvSox2 (G). Images are pseudo-colored to highlight characteristics of these cells, collectively called cnidocytes. Taken from Babonis et al. (2023).
What is this?
A sea anemone stinging cell (F; left panel) and change in cell identity following the knockout of a gene called NvSox2 (G; right panel).
How was this taken?
With a Scanning Electron Microscope. Images are pseudo-colored to highlight characteristics of these cells.
What does it do?
Sea anemones have various stinging cells, called cnidocytes, with different functions such as piercing prey for feeding or sticking to surfaces so they don’t get swept away by ocean currents.
Why should people care about this?
Piercing cells come in over 30 different sizes and shapes, all of which were thought to share a single “piercing” ancestor. But at some point in the starlet sea anemone’s evolution, a gene called NvSox2 silenced the molecular decisions that led stinging cells to become “sticky” and instead instructed them to become a specific type of “piercing” cell (F), effectively inventing a new cell type.
When NvSox2 is disabled, these “piercing” cells are restored to their ancestral “sticky” identities (G) that have been forgotten in this particular anemone’s long evolutionary history.
These results suggest that single-gene switches driving cell fate have been around for a long, long time and provide a flexible molecular mechanism for animals to adapt to new and changing environments as needed to survive. It’s plausible — maybe even likely — that other types of “piercing” cells have a similar gene-induced amnesia blocking cellular memories of a distant past.
How would you explain this to an 8-year-old?
Sea anemones (pronounced “uh-neh-moh-nees”) don’t look like you and me. They’re related to jellyfish and have special stinging cells. If you’ve ever been stung by a jellyfish, you know that can hurt!
These are pictures of two cells that come from a sea anemone. Someone has colored the cells for us so we can see them better. They’re very different from each other. Can you see how they’re different?
The smooth yellow cell on the left shoots pointy darts into the sea anemone’s food so it can eat. The dart is colored pink and blue in the picture.
The tan cell on the right has large, sticky strings that keep the sea anemone from being washed away.
When these cells are young, they’re not sure if they’re supposed to shoot small pointy darts or large sticky strings when they grow up. Do you know what you want to be when you grow up? How do you know what to choose?
These cells are told what to do with an on-off switch. When the switch is flipped on, the cell forgets how to be large and sticky and looks like the small pointy cell on the left. That’s what this sea anemone normally does. But when scientists turn the switch off, the cell suddenly remembers it should be large and sticky like the cell on the right.
Wouldn’t you like to have a switch to help you remember something that you forgot?
Switches like this can teach us how animals invent new cells. It also shows us how cells store old memories that might help them survive through hard times. When something works, you don’t want to forget it!
Where can people find more about it?
This paper was featured on Nature Communications Editors’ Highlights page. You can find the full-length article here.
BEE-ST (Bone and tEEth Spatio-Temporal growth monitoring) is a method to monitor mineralization dynamics across species. It is based on the intraperitoneal (abdominal cavity) administration of fluorescent calcium-binding dyes in an animal of interest at the specific time you want to observe newly-forming mineralized tissue. Sequential administration of dyes that fluoresce at different wavelengths (alizarin, red; and calcein, green) enables the observation of bone and tooth mineralization dynamics across time.
Where can this be found?
The technique can be applied to all tissues that undergo mineralization in various species, so the fluorescent dyes will be found in parts of bones and teeth that have developed since the administration of the dyes. The technique was developed by graduate student Marcos González López and his colleagues in Jan Křivánek’s lab at the University of Masaryk in Brno, Czechia.
How was this image taken?
The image was taken by high-resolution confocal laser-scanning microscope. Confocal microscopes use fluorescent lasers to illuminate different depth spots in your sample. By using confocal microscopy, you can obtain several images in different planes that can be put together to recreate a 3D model of your sample, in this case, the mouse molar.
What does it do?
The BEE-ST technique enables researchers to investigate how mineralized tissues (bones and teeth) develop or repair themselves after injury. This is achieved through the binding of dyes to the newly-synthesized or newly-repaired regions of bone or teeth. Once harvested, bones and teeth can be subjected to an optical-clearing protocol, enabling light to pass through them, and a couple of days later the tissue is ready to be imaged by fluorescent laser-scanning microscopy.
Why should people care about this?
The BEE-ST method is a powerful to understand how hard tissues become mineralized.
In the developmental biology and tissue engineering research communities this tool can be utilized to:
Gain a better understanding about how bone and teeth obtain their shape.
Evaluate how changes in the expression of genes, proteins or signalling pathways influence bone or tooth regeneration.
Assess the effectiveness of small molecules or drugs in promoting repair and healing of bones.
How would you explain this to an 8-year-old?
Teeth and bone have a lot of calcium in them. When they grow, or when they break and repair themselves, they add more calcium to themselves. We can use special, coloured dyes that “grab onto” growing teeth and bones to see how fast they grow or repair themselves. This way, when we look at a tooth or bone from an animal that we gave these dyes to, we can see which parts grew recently. Like you can see in the picture, when we switch between red and green dyes, we can find out how long ago each part of the tooth or bone grew, or how quickly. Look at the bones from the front and back leg of the mouse: the red parts grew before the green parts. This way, we can study how teeth and bones grow, and how they repair themselves after they break. We can also test new medicines to see if they can help bones heal more quickly after they break.
Where can people find more about it?
If people want further information on how this method works and its versatile use in all mineralized tissues across species, they can read the recent paper from the Křivánek lab at the Department of Histology and Embryology at Masaryk University in Czechia.
Flipping through the pages of Development Volume 123 Issue 1 (1996) shows the dynamics of zebrafish embryogenesis from the 2-cell stage to the 16-somite stage.
What is this?
A physical copy of Development Volume 123 Issue 1 (1996), with a flipbook at the upper corner of the issue showing zebrafish embryogenesis over 17 hours from the 2-cell stage to the 16-somite stage.
Where can this be found?
The Company of Biologists office in Cambridge, UK
Why should people care about this?
Consisting of 37 papers, this zebrafish special issue presented the results of two large screens for zebrafish mutants. The papers describe about 1500 mutations in more than 400 new genes involved in a wide range of processes that govern development and organogenesis. The mutants described in this issue provide a rich resource for many zebrafish laboratories to study embryogenesis, neuronal networks, regeneration and disease.
How would you explain this to an 8-year-old?
What happens to the first 17 hours of the life of a little zebrafish? In this science book, when you flip through the pages, you can see how the zebrafish grows from just two cells to 16 cells by the end of the book, where you can start to see the shapes of the eyes and brain of the zebrafish.
These zebrafish may look very different from us humans, but they are actually very useful for scientists to learn more about the general rules of how we grow, and what happens to us if something inside us is not working properly.
Where can people find more about it?
For more details about the making of the ‘flipbook’, read this article.
A recent Cell paper finds that proteostasis governs differential temperature sensitivity across cell types in zebrafish embryos. First author Mike Dorrity tells us more about the story behind the paper.
How did you come to join Cole Trapnell’s lab and how did the project get started?
My PhD lab shared a work area with Cole’s in Seattle, so I spent a lot of time chatting with his group. One time, they were all heading out for pizza + drinks, and, being a graduate student, I tagged along hoping for an easy meal. As I was a bit out of place, some jokes were made about me being a new lab member, so Cole played along and asked: “Since you’re joining the lab, what are you going to work on?” He only seemed to be half-joking, so I had no choice but to give a half-serious response: “how temperature influences developmental robustness, something like that.” I believe that got the ball rolling. After discussing with other Trapnell lab folks working on fish, we hatched initial plans for temperature experiments.
What was known about how developing zebrafish embryos respond to temperature stress before your work?
Well, I have to split that one up a bit: (1) I think every zebrafish researcher knows something about how they respond to temperature, since slowing or speeding up development is practically very useful. Do you know what time you have to wake up to study 15-somite stage animals? The relationship between temperature and the rate of development is well-documented, and I refer to the chart in Kimmel et al 1995 constantly. (2) For temperature stress, the outcome is a bit different – there are developmental phenotypes that pop up over and over again. We knew about some of these phenotypes, such as a bend in the body axis, and, from previous work, even knew some of the molecular consequences of temperature stress: heat-shock protein induction, regulation of protein homeostasis.
Can you summarise the findings of the paper in one paragraph?
All in all, I think it can be summarized in one sentence: cell types do not respond equally to temperature. That sounds trivial, but it’s counterintuitive in the context of what we know about the heat shock response (uniform across cells) and of what we know about the acceleration of developmental rate at increased temperature (must be uniform-ish, as embryos are still viable). Basically, when you look closely at all cells at these sub heat-shock temperatures, you can see that temperature destabilizes the fidelity or robustness of development of certain cell types more than others. These cell type-specific sensitivities might not be so obvious when looking at the whole embryo under a stereoscope, but they explain the common failure modes of embryogenesis and the phenotypes that emerge as embryos approach the limits of developmental robustness.
Were you surprised to find that some cell types display accelerated developmental rates more than other cell types in response to the same elevated temperature?
Absolutely, this result completely changed how I thought of the problem. I come from a background informed by the biochemistry and molecular control of the heat shock response – the dogma there, rightfully so, is that all cells more or less mount the same response to stress: stop making proteins and prevent the existing ones from falling into misfolded, non-functional states. That makes good sense, but the embryo context is so different from something like yeast; different cells have drastically different functions and thus express a unique repertoire of proteins to carry out those functions. From that perspective, it’s not so surprising that cells respond differently. Beyond that, cells have many ways to sense temperature that can also vary in the embryo. For example, plasma membrane fluidity increases as a function of temperature, but this increased fluidity is also necessary for migratory cell types.
Can you describe how you captured phenotypic variability across individuals raised at different temperatures?
Yes! This technique is indebted to previous work in the Trapnell lab, [Srivatsan, McFaline-Figueroa, Ramani et al 2020] as well as efforts by Lauren and Sanjay in the “sister” publication to this one [Saunders, Srivatsan et al 2023]. Basically, the trick is: during embryo dissociations, we add barcoded, single-stranded DNA oligos and fix them to nuclei that come from a single embryo. This ensures that we can link all those cells back to the embryo-of-origin after our single-cell RNA-seq library preparation. Our phenotype in this case is actually whole-embryo cell composition, and you can only get measures of variability if you measure many individual fish (n > 100). This molecular trick unlocks individual-level data, and we can then perform statistics on the resulting cell counts, which would be otherwise be challenging to acquire for all cell types.
Can you postulate about the mechanisms through which the UPR controls temperature-induced developmental acceleration?
I would be happy to, and I encourage any potential reader to reach out if they’d like to discuss further, because this is an exciting new direction for us. The unfolded protein response, or the integrated stress response more broadly, has access to global control of protein synthesis in the cell. Under protein folding stress in the ER, UPR will put the brakes on translation. Control of translation rate (as well as protein degradation rate), has been linked to species-specific differences in the control of developmental rate, so I think any mechanism that feeds into protein synthesis rate has the potential to affect timing (we also saw slowdown of development when we inhibited translation). I think the sensing of protein concentration, protein synthesis, and protein folding in the ER is an efficient proxy for temperature. If you take away this sensing apparatus, the embryo doesn’t accelerate like it’s supposed to, despite being raised at a higher temperature.
Did you have any particular result or eureka moment that has stuck with you?
For me, it’s that an enormous amount of variation in the developmental-series scRNA-seq data is explained by the time or stage of the embryo. Again, this may sound trivial – of course gene expression patterns change over time! What has really stuck with me is how developmental timing, cell composition and transcription go hand-in-hand, even down to timescales of minutes (see Figure). Being immersed in the quantitative/statistical thinking of Cole’s lab made me realize how this simple observation can profoundly affects interpretation of your results; many factors (time, temperature, cell type..) are squabbling over the variation in your data, and it’s up to you to break them up and see what all the fuss is about.
And the flipside: were there any moments of frustration or despair?
Much of this project was completed between the peaks of the initial strain and Delta variant of SARS-CoV-2; despair was unavoidable. On the other hand, the constant questioning during those months was balanced by the task of being a scientist. I was very lucky to have co-authors with me at 2am in N95s, wearing headlamps (I cannot remember why) to dissociate embryos. The ensuing virtual meetings, discussions, optimizations, and laughs were essential in reminding me how science feels at its best: a community of people finding answers in the face of uncertainty.
What’s next for this story? And what’s next for you personally?
What’s next is: why are some cells more sensitive to temperature? Is this at all meaningful in the evolutionary context of temperature adaptation? Thankfully, I just started my group at the EMBL (https://www.dorrity-lab.com/) in Heidelberg, Germany surrounded by amazing colleagues and fellows to pursue these questions. If these questions sound exciting to you, reach out!
Hi! My name is Teodora and I am the new Sustainable Conferencing and Communications Officer from The Company of Biologists.
Since I joined The Company of Biologists, I have worked to improve the sustainability strategy of our events in order to decrease our carbon footprint. If you are interested in making your events with a lower environmental impact, we are happy to support you on this journey as well!
Feel free to email me at sustainability@biologists.com if you do not know where to start, and I am happy to help you start building your sustainable strategy for your events.
We are also keen to support your sustainability progress in event organising with our Sustainable Conferencing Grant. If you have any innovative idea on how decreasing the carbon footprint of your next scientific event, we would like to see your application. Here is a compete list of what we fund with the Sustainable Conferencing Grant:
Measures to reduce the carbon footprint of travel (up to £1,000)
for example, removing the necessity to fly by asking speakers to present virtually, or maximising the number of non-local speakers travelling by train or other relatively low-carbon transport
Additional cost of technology (up to £2,500)
for example, rental of a virtual platform or equipment to host a virtual element, IT and associated support/services
we are particularly keen to fund innovative technologies or innovative uses of existing technologies
Innovative feature (up to £2,500)
for example, the development of an app to enhance the experience of virtual attendees
Other (up to £1,000)
measures to improve sustainability that are not covered by any of the other categories
As we get to the end of 2023, the Node, preLights and FocalPlane, the three community sites of The Company of Biologists, would like say a massive thank you to everyone who have read and contributed to the three sites in the past year!
To share some festive fun, and to encourage you to revisit some of the content we put out in 2023, we’ve come up with an end-of-year quiz.
Complete the quiz for a chance to win a goodie bag prize consisting of the Node postcards, the Node Network jigsaw puzzle, FocalPlane notebook, preLights and Biology Open highlighters, a Foldscope and more!
All the answers can be found on the three community sites or in our journals.
Have fun and see you in 2024, Joyce (Community Manager of the Node)
Finish our end-of-year quiz for a chance to win a goodie bag prize including the Node postcards, preLgihts highlighters, FocalPlane notebooks, a Foldscope and more. (Christmas tree in photo not included, unfortunately shipping costs will be over our budget!) (No Ratings Yet) Loading...
“We’ve wrapped up these conversational crackers into a scientific smorgasbord, an allelic amuse-bouche, a genetic gallimaufry, if you will, into this bonus episode!”
If you enjoy the show, please do rate and review on Apple podcasts and help to spread the word on social media. And you can always send feedback and suggestions for future episodes and guests to podcast@geneticsunzipped.com Follow us on Twitter – @geneticsunzip
In the recent BSDB-the Node virtual art exhibition, Christoph Markus Haefelfinger’s ‘The backbone of stem cell derived embryos’ was selected as the Judges’ Choice runner-up in the ‘Scientific images’ category. We briefly caught up with Christoph to find out more about his research and the story behind the image.
The backbone of stem cell derived embryos Christoph Markus Haefelfinger (California Institute of Technology)
The cytoskeletal structure of preimplantation embryos demonstrated in a reconstruction of a stem cell derived mouse blastoid. After fixation, the structure was immunostained for f-actin (phalloidin, grey) and the inner cell mass (Oct4, red), then imaged.
What is your background? I am a final year medical Student from Switzerland, currently applying for a PhD in developmental and stem cell biology in the UK. At the time I took my confocal image, I was a Summer Undergraduate Research Fellow in the laboratory of Professor Magdalena Żernicka-Goetz at the California Institute of Technology.
What are you currently researching on? I am continuing my work at the Żernicka-Goetz lab at the University of Cambridge in parallel to clinical placements at the Universities of Cambridge and Oxford, researching preimplantation development using a mouse stem cell derived embryo model. More precisely, I aim to help solidify the scientific confidence in utilising bioengineered embryo models to study specific developmental questions.
Can you tell us more about the story behind your image ‘The backbone of stem cell derived embryos’? To me, the image signifies the culmination of my ten week fellowship at Caltech learning the ins and outs of stem cell derived embryos, and is one of my proudest achievements. I had a truly wonderful and eye-opening experience grounded in cutting-edge research and exploring the Western USA with amazing friends and colleagues, and many of these emotions are strongly tied to my picture. I am therefore even more proud and grateful for the amazing feedback by the jury and the public – it is truly a fantastic feeling to have so many of you appreciate my image which is so close to my heart!
What is your favourite technique? Choosing from the techniques I had the chance to learn and apply myself as an undergraduate researcher, I must go for live imaging using fluorescent reporters. I believe there are few techniques that hold the promise to not only provide quantifiable data, but to spatiotemporally visualize highly complex processes in an unparalleled beauty. Especially in the context of developmental biology, I know of no other method that could capture the dance of life in a more mesmerizing way, making it an easy choice for me.
What excites you the most in the field of developmental and stem cell biology? I am captivated by the fact that we all originate from a single cell. To me it sometimes still is an abstract thought, and seeing an embryo develop – human, mouse, or stem cell derived – excites me every time. This enthusiasm translates into my strong curiosity for cell fate acquisition, and how it interrelates with self-organisation, spatiotemporal crosstalk, and its regulatory foundation on an omics level. I am therefore truly excited to continue researching development in my PhD.
Castle of Dreaming Dragons This began as a small pencil sketch in May 2019 and went through a series of transitions to the final piece, which was finished in June 2020. It ended up being inked digitally, and painted with watercolours, which was an odd combination to choose but I was pleased with how it turned out. I was really pleased to be able to exhibit it in the BSDB virtual art exhibition this year.
Can you tell us about your background and what you work on now?
I’m from the UK, and I study the genetics of progressive hearing loss in the lab of Professor Karen Steel at King’s College London. The project I have been working on most recently involved analysing sequence data from several large human cohorts and developing different methods to identify genes and variants which might be contributing to the different types of hearing loss observed in the participants.
This is one of the rare images directly based on my research. It shows SNPs from a region on chromosome five from a mouse of unknown background (leftmost column), 15 inbred strains and 7 wild-derived strains. Inbred and wild-derived strain data was obtained from Jax (Center for Genome Dynamics (CGD). SNP data from Mouse Diversity Genotyping Array, 582,000 locations for 72 strains of mice. MPD:CGD2. Mouse Phenome Database web site, The Jackson Laboratory, Bar Harbor, Maine USA. http://phenome.jax.org, Nov, 2010.). The image was generated using perl (green=G, red=A, blue=C, yellow=T). It was exhibited at the the BSDB/GenSoc art exhibition in 2021, which I very much enjoyed being part of.
Were you always going to be a scientist?
I remember not knowing what I wanted to do when I grew up, but I studied the subjects I enjoyed most and I’m pretty happy with where I ended up. I did take a side trip through computer science between my undergraduate degree and my PhD, which turned out to be very useful further down the line.
And what about art – have you always enjoyed it?
I have always enjoyed doodling, to the point where I used to worry about being given a new rough book at school – the teachers always checked to make sure the old one had been used properly and I didn’t think covering the pages with horse doodles counted! And I have always told stories, but usually just to myself.
The chapter title page from another illustrated story I’m working on, “Looking for the Sun”.
What or who are your most important artistic influences?
I would say the most important artistic influences on me are writers such as Lois McMaster Bujold and Martha Wells, and artists like Kaoru Mori and Hitoshi Ashinano, but they are the tip of the iceberg. If I read something I like, it’s hard not to be influenced by it.
How do you make your art?
I mostly make comics, and I use coloured pencils to draw, then I ink over the pencils with a dip pen, brush, and ink. For colour work, I use watercolour paints and alcohol markers. But in both cases, I scan and edit the results digitally.
A page from my illustrated novel “The Emperor’s Hound”, showing the first meeting of the protagonists.
Does your art influence your science at all, or are they separate worlds?
I don’t think my art and science influence each other directly, but I find keeping a good balance between them means I can do both better, if that makes sense. When it comes to preparing figures for papers, or posters for conferences, my experience with making and printing comics is invaluable.
An illustration from my current webcomic, “Nobody’s Library”.
What are you thinking of working on next?
I actually started out wanting to write books rather than comics, because I was a novel reader as a child rather than a comic reader (that came later). I have recently been experimenting with prose again, and have produced an illustrated novel. I’d like to keep doing that, and I have an idea I very much want to develop… when I get some of my existing projects finished!
I read the name of Pere Alberch for the first time while leafing through a collection of articles on Ecology and Evolution edited by the Universidad Autónoma de México [1]. At the time I was a bachelor’s student of Biology at the University of Turin, desperately collecting material for my final dissertation on the role of physical parameters in shaping form during embryo development. In the paper “Evolution and complexity: developmental constrains” by B. Luque & J. Bascompte, I found out that Pere was a “blighted theoretician of development and experimental embryologist” who did seminal work on thedevelopment and evolution of the tetrapod limb. Despite having only recently closed my textbooks of Developmental and Evolutionary Biology, I had no idea that Pere was one of the founding fathers of Evo-Devo, a field that aims to connect evolutionary novelty to developmental dynamics, i.e. “phylogeny” to “ontogeny” [2]. To my surprise, most of his work was indeed rarely cited and his name would have been certainly forgotten were it not for the visionary power of his ideas and the determination of his scientific disciples, who so tenaciously kept those ideas alive.
Almost ten years later, I have had the chance to follow a celebrative symposium on Pere’s work, set in Barcelona, just few kilometres from where he was born. “Genes, cells and embryos in development and evolution: Pere Alberch 25 years on” took place at Barcelona Biomedical Research Park (PRBB), onthe 9th and 10th November 2023, organised by Alfonso Martinez-Arias (Universitat Pompeu Fabra), Denis Duboule (École Polytechnique Fédérale de Lausanne) and James Sharpe (EMBL Barcelona). As the title suggests, the symposium aimed to cover each of the biological scales which are relevant to the study of development and evolution of form (the genetic, cellular and tissue scale), whose tight integration at the embryo level had been so consistently emphasized by Pere. Here is the link to the event: https://eventum.upf.edu/94510/detail/genes-cells-and-embryos-in-development-and-evolution-pere-alberch-25-years-on.html.
Poster of the conference.
Who other than Denis Duboule could kick off the first session, entitled “Constraints and the hourglass”? His talk highlighted how the range of morphologies in the early stages of vertebrate embryonic development, during the so-called “phylotypic stage”, is restricted already at the chromatin level, with the Hox timer being one of the main agents constraining the ‘neck’ of the hourglass model. The presence of phenotypic invariance, of which the “phylotypic stage” is an example, was what intrigued Pere the most, together with the study of abnormal phenotypes or “monsters” as a powerful tool to get a glimpse into otherwise hidden developmental rules [3]. The next speaker, Freiton Gallis (Leiden Biodiversity Center), built her research upon these two aspects, focusing on the conservation of the number of cervical vertebrae in mammals and on the analysis of vertebral defects such as cervical ribs. Arkhat Abzhanov (Imperial College London) illustrated his work on cranial shape variation in amniotes, followed by Michael Richardson (Leiden University) who fascinated the audience with a story of coevolution between a parasitic fish and the mussels that host its peculiarly-shaped eggs.
Patrick Lemaire (Centre de Recherche en Biologie Cellulaire de Montpellier) used the “parameter space” proposed by Pere in 1991 [4] to guide us through the world of ascidian embryos which display an incredible invariance in morphologies despite the extreme genetic divergence among species and their phenotypic diversity as adults. Margarita Cardoso Moreira (The Francis Crick Institute), whose recently established lab explores the evolution of sexual dimorphism, highlighted how sex differences can be traced down even to the cellular level! Her talk was followed by Camille Berthelot (Institut Pasteur), whose lab exploits organoid models of the uterine epithelium to study a trait that, similarly to sex differences, evolves quite rapidly: embryo implantation. The session, entitled “Of genes and cells”, was finally closed by the provocative talk of Iñaki Ruiz-Trillo (Universitat Pompeu Fabra) who clearly stated that we are still quite far from understanding what the unicellular ancestor of animals, the source of all the phenotypic diversity we witness at the present day, looked like. We left for lunch with a glimpse of hope that, through the use of metagenomics and the sampling of new taxa of unicellular organisms, we will be able to better address the origins of multicellularity.
The afternoon session was a journey in Pere’s life, fortune and friends. It started with the talk of Gerd Müller (University of Vienna), one of Pere’s closest collaborators. His presentation showcased some of his old work with Pere on the archosaur limb [5] together with some more recent work on polydactyly, and was interspersed with pictures of their fruitful meetings and forays. While the philosopher Laura Nuño de la Rosa (Universidad Complutense de Madrid) explained the reasons why Pere may have been forgotten by the scientific community over the years, despite his relevance for the Evo-Devo field, Diego Rasskin-Gutman (Universitat de València) clearly expressed why he cannot forget his mentor and how Pere’s ideas deeply influenced the work of his own lab, including the development of the Anatomical Network Analysis (AnNA) for topological analysis of organismal form. In the last years of his life, before his premature death in 1998, Pere became director of the Natural History Museum of Madrid. Rafael Zardoya, the current director of the museum, gave the last talk of the session, showing the crucial role that Pere played in restoring the Museum to its former glory and how deeply his decisions are still impacting the organization of the museum today.
Day 1 of the conference closed with a keynote lecture from Neil Shubin, who was one of Pere’s first PhD students at Harvard University. His engaging talk gripped the minds of the audience, who very much enjoyed the narration of the discovery of the Tiktaalik fossil, the first fish venturing onto land. He mostly focused on his work on fin-to-limb transition in vertebrates and hinted to some new work he is envisioning to do on salamander limbs, which relates to his PhD project in Pere’s lab.
Neil Shubin guides the audience through the characteristics of the Tiktaalik (photo credits: Marta Vila Cejudo).
Ricard Solé (Universitat Pompeu Fabra) kicked off Day 2 of the conference, arguing that the logic of life is predictable since life itself has its own constraints: in order for life to exist, even in another planet, certain conditions need to be met. We came back to earth for the rest of the session, in particular to life in the waters: Berta Verd (University of Oxford), Joost Woltering (University of Konstanz) and Emilia Santos (University of Cambridge) each illustrated their research on teleost fishes. Verd and Santos both exploit cichlid fishes as model organisms to study the evolution of two different morphological traits: vertebral counts and pigmentation patterns, respectively. Interestingly, cichlid fishes display a wide phenotypic diversity despite bearing similar genetics, falling on the opposite side of the spectrum with respect to ascidians. Joost Woltering uses a variety of teleost fish models in his lab to look at morphogenesis and evolution of their dermal skeleton, with particular attention to fins. With James Sharpe’s talk we shifted from fins to limbs, having the chance of listening to some new insights on digit pattern formation, an intriguing follow-up to some of Pere’s old work [6].
The task to close the conference was given to another speaker that has been deeply influenced by Pere’s work: Cliff Tabin. He surprised everyone by announcing that his talk would focus on the physical forces shaping gut development, rather than the topic of heterochronic shifts in limb development. As an homage to Pere, he showed how the circular model of morphogenesis Pere proposed in 1989 [3] can elegantly explain the process of villification in chick gut tube, a topic that the Tabin lab has been working on for over 15 years. Pere stated that genes undoubtedly influenced cell properties and thus morphogenesis by contributing to tissue geometry, but that tissue geometry and so the morphogenetic outcome (the ‘structure’ itself), feeds back into gene regulation, making morphogenesis a rather dynamic process and, far less simplistic than what was previously thought. This was my favourite talk of the conference, since it unleashed the true revolutionary power of Pere’s ideas and their relevance in the study of development and evolution.
Cliff Tabin elaborating on the schematic of the circular view of morphogenesis proposed by Pere Alberch (photo credits: Marta Vila Cejudo).
As Laura Nuño de la Rosa explained on Day 1 of the conference, there are a number of reasons for the aura of mystery around Pere’s work, which despite his relevance for the field of Developmental and Evolutionary Biology is very poorly cited. These include the fact that Pere had to close his lab in Harvard for lack of funding, his rather quarrelsome personality that did not make him popular among collaborators, and his premature death in 1998. By the end of the meeting, I understood more clearly why I had only encountered his name in a hidden collection of papers rather than in the textbooks or classes where I had first about Evo-Devo in University. As Alfonso Martinez-Arias stated in his closing remarks, this symposium proved that, despite “the slings and arrows of fortune”, ideas can outlive their creators and do not fade despite their work being ignored by the scientific community. The circular view of causation in morphogenesis, development as a new level of selection between genotype and phenotype, the genotype-phenotype maps, the importance of ‘monsters’: all of this we owe to Pere and we can only thank him for promoting avenues of research that are so relevant today.
References to Pere’s work:
[1] Benítez M. et al., ‘Frontiers in Ecology, Evolution and Complexity’, Copit-arXives, Mexico DF 2014. [2] Alberch et al., ‘Size and shape in ontogeny and phylogeny’, Paleobiology, 1979, 5(3):296-317. [3] Alberch P., ‘The logic of monsters: evidence for internal constraint in development and evolution’, Geobios, 1989, 12:21–57. [4] Alberch P, ‘From genes to phenotype: Dynamical systems and evolvability’, Genetica, 1991, 84: 5–11. [5] Müller G. and Alberch P., ‘Ontogeny of the limb skeleton in Alligator mississippiensis. Developmental invariance and change in the evolution of archosaur limbs’, Journal of Morphology, 1990, 203: 151–164. [6] Alberch P. et al, ‘Size dependence during the development of the amphibian foot: Colchicine-induced digital loss and reduction’, Journal of Embryology and Experimental Morphology, 1983, 76: 177–197.
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