Evo-devo Research Research Articles

Homoplasy as an Evolutionary Process: An Optimistic View on the Recurrence of Similarity in Evolution

AbstractIn the cladistic literature, there is a recurrent perspective that considers homoplasy as something undesirable. Homoplasy, according to this view, is believed to obscure homologies that may lead to synapomorphies. Some cladists often call homoplasies an ad hoc hypothesis or an “error in our preliminary assignment of homology.” Consequently, homoplasy is generally regarded negatively, hindering further investigations, because it matters little whether a character subject to homoplasy is a convergence, a parallelism, or a reversal, since they all fall within the problematic homoplastic category. Nixon and Carpenter developed one of the recent arguments supporting this vision. In this context, I will argue that phylogenetics, being a part of evolutionary biology, must be compatible with its principles. Therefore, I will discuss the idea that homoplasy is more complex than just nonhomology, sometimes even constituting evidence of common ancestry (e.g., parallelism). I will put forward the thesis that it is crucial to differentiate instances of convergence, parallelism, and reversions by incorporating recent advances from EvoDevo research. Ultimately, this approach aims to demonstrate that evolutionary biology and phylogenetics mutually complement each other and assist in providing different lines of evidence that can be used to test different evolutionary hypotheses.

Old hypotheses and theories at the heart of current evo-devo research.

Old hypotheses and theories at the heart of current evo-devo research.

What one genus of showy moths can say about migration, adaptation, and wing pattern

The Ornate Moth, Utetheisa ornatrix, has served as a model species in chemical ecology studies for decades. Like in the widely publicized stories of the Monarch and other milkweed butterflies, the Ornate Moth and its relatives are tropical insects colonizing whole continents assisted by their chemical defenses. With the recent advances in genomic techniques and evo-devo research, it is becoming a model for studies in other areas, from wing pattern development to phylogeography, from toxicology to epigenetics. We used a genomic approach to learn about Utetheisa's evolution, detoxification, dispersal abilities, and wing pattern diversity. We present an evolutionary genomic analysis of the worldwide genus Utetheisa, then focusing on U. ornatrix. Our reference genome of U. ornatrix reveals gene duplications in the regions possibly associated with detoxification abilities, which allows them to feed on toxic food plants. Finally, comparative genomic analysis of over 100 U. ornatrix specimens from the museum with apparent differences in wing patterns suggest the potential roles of cortex and lim3 genes in wing pattern formation of Lepidoptera and the utility of museum-preserved collection specimens for wing pattern research.

Problems with Paralogs: The Promise and Challenges of Gene Duplicates in Evo-Devo Research.

Gene duplicates, or paralogs, serve as a major source of new genetic material and comprise seeds for evolutionary innovation. While originally thought to be quickly lost or nonfunctionalized following duplication, now a vast number of paralogs are known to be retained in a functional state. Daughter paralogs can provide robustness through redundancy, specialize via sub-functionalization, or neo-functionalize to play new roles. Indeed, the duplication and divergence of developmental genes have played a monumental role in the evolution of animal forms (e.g., Hox genes). Still, despite their prevalence and evolutionary importance, the precise detection of gene duplicates in newly sequenced genomes remains technically challenging and often overlooked. This presents an especially pertinent problem for evolutionary developmental biology, where hypothesis testing requires accurate detection of changes in gene expression and function, often in nontraditional model species. Frequently, these analyses rely on molecular reagents designed within coding sequences that may be highly similar in recently duplicated paralogs, leading to cross-reactivity and spurious results. Thus, care is needed to avoid erroneously assigning diverged functions of paralogs to a single gene, and potentially misinterpreting evolutionary history. This perspective aims to overview the prevalence and importance of paralogs and to shed light on the difficulty of their detection and analysis while offering potential solutions.

Ultrastructural and immunocytochemical evidence of a colonial nervous system in hydroids.

As the sister group to all Bilateria, representatives of the phylum Cnidaria (sea anemones, corals, jellyfishes, and hydroids) possess a recognizable and well-developed nervous system and have attracted considerable attention over the years from neurobiologists and evo-devo researchers. Despite a long history of nervous system investigation in Cnidaria, most studies have been performed on unitary organisms. However, the majority of cnidarians are colonial (modular) organisms with unique and specific features of development and function. Nevertheless, data on the nervous system in colonial cnidarians are scarce. Within hydrozoans (Hydrozoa and Cnidaria), a structurally "simple" nervous system has been described for Hydra and zooids of several colonial species. A more complex organization of the nervous system, closely related to the animals' motile mode of life, has been shown for the medusa stage and a few siphonophores. Direct evidence of a colonial nervous system interconnecting zooids of a hydrozoan colony has been obtained only for two species, while it has been stated that in other studied species, the coenosarc lacks nerves. In the present study, the presence of a nervous system in the coenosarc of three species of colonial hydroids - the athecate Clava multicornis, and thecate Dynamena pumila and Obelia longissima - was studied based on immunocytochemical and ultrastructural investigations. Confocal scanning laser microscopy revealed a loose system composed of delicate, mostly bipolar, neurons visualized using a combination of anti-tyrosinated and anti-acetylated a-tubulin antibodies, as well as anti-RF-amide antibodies. Only ganglion nerve cells were observed. The neurites were found in the growing stolon tips close to the tip apex. Ultrastructural data confirmed the presence of neurons in the coenosarc epidermis of all the studied species. In the coenosarc, the neurons and their processes were found to settle on the mesoglea, and the muscle processes were found to overlay the nerve cells. Some of the neurites were found to run within the mesoglea. Based on the findings, the possible role of the colonial nervous system in sessile hydroids is discussed.

Nectary development in Cleome violacea.

Nectaries are a promising frontier for plant evo-devo research, and are particularly fascinating given their diversity in form, position, and secretion methods across angiosperms. Emerging model systems permit investigations of the molecular basis for nectary development and nectar secretion across a range of taxa, which addresses fundamental questions about underlying parallelisms and convergence. Herein, we explore nectary development and nectar secretion in the emerging model taxa, Cleome violacea (Cleomaceae), which exhibits a prominent adaxial nectary. First, we characterized nectary anatomy and quantified nectar secretion to establish a foundation for quantitative and functional gene experiments. Next, we leveraged RNA-seq to establish gene expression profiles of nectaries across three key stages of development: pre-anthesis, anthesis, and post-fertilization. We then performed functional studies on five genes that were putatively involved in nectary and nectar formation: CvCRABSCLAW (CvCRC), CvAGAMOUS (CvAG), CvSHATTERPROOF (CvSHP), CvSWEET9, and a highly expressed but uncharacterized transcript. These experiments revealed a high degree of functional convergence to homologues from other core Eudicots, especially Arabidopsis. CvCRC, redundantly with CvAG and CvSHP, are required for nectary initiation. Concordantly, CvSWEET9 is essential for nectar formation and secretion, which indicates that the process is eccrine based in C. violacea. While demonstration of conservation is informative to our understanding of nectary evolution, questions remain. For example, it is unknown which genes are downstream of the developmental initiators CvCRC, CvAG, and CvSHP, or what role the TCP gene family plays in nectary initiation in this family. Further to this, we have initiated a characterization of associations between nectaries, yeast, and bacteria, but more research is required beyond establishing their presence. Cleome violacea is an excellent model for continued research into nectary development because of its conspicuous nectaries, short generation time, and close taxonomic distance to Arabidopsis.

A Study on Plant Structure

This paper propose image processing algorithms to recognize The Plant structure in Plant Kingdom. Anatomy is one of the oldest disciplines of plant science, and there is a huge amount of accumulated knowledge. At the same time, anatomy is highly important as a linking medium between several key branches of modern plant science. Detailed anatomical studies, these days using X-ray microtomography, allow much more detailed understanding of plant fossils and thus facilitate the accumulation of greatly extended non-molecular data sets. The use of anatomy is one of most efficient ways of increasing the number of characters in data sets employed to link fossil and extant plants. This link is essential for achieving the ambitious goal of acquiring a holistic knowledge of plant evolution combining the direct, but fragmentary evidence from the fossil record and the indirect, though highly informative data of molecular phylogenetics and phylogenomics. Anatomy is one of key tools of evo-devo research. Indeed, analyses of gene expression patterns are performed using anatomical techniques. More importantly, developmental biology of plants explores functioning of plant meristems and aspects of cell and tissue differentiation, the topics that have a long history of research in the framework of plant anatomy. Anatomy provides detailed information of the developmental processes in extant and extinct plants. Obviously, the detailed knowledge assembled through centuries of anatomical research has great perspectives of use in evolutionary developmental biology. Many theories developed in plant anatomy can be tested using molecular tools (e.g. Povilus et al., 2020), but it is important to pose the questions. Anatomy has many implications for plant physiology and ecology and provides an excellent tool for investigating historical aspects of these disciplines, including those related to climate change.

EDomics: a comprehensive and comparative multi-omics database for animal evo-devo.

Evolutionary developmental biology (evo-devo) has been among the most fascinating interdisciplinary fields for decades, which aims to elucidate the origin and evolution of diverse developmental processes. The rapid accumulation of omics data provides unprecedented opportunities to answer many interesting but unresolved evo-devo questions. However, the access and utilization of these resources are hindered by challenges particularly in non-model animals. Here, we establish a comparative multi-omics database for animal evo-devo (EDomics, http://edomics.qnlm.ac) containing comprehensive genomes, bulk transcriptomes, and single-cell data across 40 representative species, many of which are generally used as model organisms for animal evo-devo study. EDomics provides a systematic view of genomic/transcriptomic information from various aspects, including genome assembly statistics, gene features and families, transcription factors, transposable elements, and gene expressional profiles/networks. It also exhibits spatiotemporal gene expression profiles at a single-cell level, such as cell atlas, cell markers, and spatial-map information. Moreover, EDomics provides highly valuable, customized datasets/resources for evo-devo research, including gene family expansion/contraction, inferred core gene repertoires, macrosynteny analysis for karyotype evolution, and cell type evolution analysis. EDomics presents a comprehensive and comparative multi-omics platform for animal evo-devo community to decipher the whole history of developmental evolution across the tree of life.

Development and Evolution of Unisexual Flowers: A Review.

The development of unisexual flowers has been described in a large number of taxa, sampling the diversity of floral phenotypes and sexual systems observed in extant angiosperms, in studies focusing on floral ontogeny, on the evo-devo of unisexuality, or on the genetic and chromosomal bases of unisexuality. We review here such developmental studies, aiming at characterizing the diversity of ontogenic pathways leading to functionally unisexual flowers. In addition, we present for the first time and in a two-dimensional morphospace a quantitative description of the developmental rate of the sexual organs in functionally unisexual flowers, in a non-exhaustive sampling of angiosperms with contrasted floral morphologies. Eventually, recommendations are provided to help plant evo-devo researchers and botanists addressing macroevolutionary and ecological issues to more precisely select the taxa, the biological material, or the developmental stages to be investigated.

Post-genomics, Evo-Devo and the recurrence of teleologic thought†

Abstract The post-genomic era raises questions about neo-Darwinian genetic determinism. Instead, open aspects of macroevolution become intelligible by Evo-Devo research. At all developmental levels, self-organization acts robustly towards “wholeness”, as exemplified by organoid technologies. In retinal reaggregates histotypical features are reached along different formative routes. Thus, tissue formation is not merely gene-directed, but channeled by unpredictable external conditions. These insights restrict conceptions of onto- and phylogenesis. Neither is characterized by unlimited randomness nor by finite genocentrism. A re-examination of Driesch’s drive to wholeness, i.e., robustness and intentionality, appears timely, while his teleologic postulates remain undecidable by reductionist reasoning.

Spinal malformations in a naturally isolated Neotropical fish population.

Fish populations that reside in completely isolated freshwater ecosystems are rare worldwide. The Vila Velha State Park (VVSP), located in southern Brazil, is recognized for its arenitic formations called sinkholes (furnas), which are completely isolated. Fish populations within, such as those of Psalidodon aff. fasciatus, often develop vertebral malformations due to this isolation from other conspecifics and other species. In this study, we analyzed geometric morphology in digital radiographs to identify congenital deformations of Psalidodon aff. fasciatus in Furna 2 of VVSP. We found many fish with spinal deformities, including wide variation in the number of caudal vertebrae and corporal deformations related to a flattened body and spinal curvature. Females were more affected than males. We also demonstrated that these deformations reflect inbreeding and an absence of gene flow in the population. In conclusion, isolated populations such as fish species in furnas are potential models for evo-devo research.

Optical Clearing and Light Sheet Microscopy Imaging of Amphioxus.

Cephalochordates (amphioxi or lancelets) are representatives of the most basally divergent group of the chordate phylum. Studies of amphioxus development and anatomy hence provide a key insight into vertebrate evolution. More widespread use of amphioxus in the evo–devo field would be greatly facilitated by expanding the methodological toolbox available in this model system. For example, evo–devo research on amphioxus requires deep understanding of animal anatomy. Although conventional confocal microscopy can visualize transparent amphioxus embryos and early larvae, the imaging of later developmental stages is problematic because of the size and opaqueness of the animal. Here, we show that light sheet microscopy combined with tissue clearing methods enables exploration of large amphioxus specimens while keeping the surface and the internal structures intact. We took advantage of the phenomenon of autofluorescence of amphioxus larva to highlight anatomical details. In order to investigate molecular markers at the single-cell level, we performed antibody-based immunodetection of melanopsin and acetylated-α-tubulin to label rhabdomeric photoreceptors and the neuronal scaffold. Our approach that combines light sheet microscopy with the clearing protocol, autofluorescence properties of amphioxus, and antibody immunodetection allows visualizing anatomical structures and even individual cells in the 3D space of the entire animal body.

Amphibian Hormones, Calcium Physiology, Bone Weight, and Lung Use Call for a More Inclusive Approach to Understanding Ossification Sequence Evolution

Skeleton plays a huge role in understanding how vertebrate animals have diversified in phylogeny, ecology and behavior. Recent evo-devo research has used ossification sequences to compare skeletal development among major groups, to identify conserved and labile aspects of a sequence within a group, to derive ancestral and modal sequences, and to look for modularity based on embryonic origin and type of bone. However, questions remain about how to detect and order bone appearances, the adaptive significance of ossification sequences and their relationship to adult function, and the utility of categorizing bones by embryonic origin and type. Also, the singular focus on bone appearances and the omission of other tissues and behavioral, ecological and life history events limit the relevance of such analyses. Amphibians accentuate these concerns because of their highly specialized biphasic life histories and the exceptionally late timing, and high variability of their ossification sequences. Amphibians demonstrate a need for a whole-animal, whole-ontogeny approach that integrates the entire ossification process with physiology, behavior and ecology. I discuss evidence and hypotheses for how hormone mediation and calcium physiology might elicit non-adaptive variability in ossification sequence, and for adaptive strategies to partition larval habitats using bone to offset the buoyancy created by lung use. I also argue that understanding plasticity in ossification requires shifting focus away from embryonic development and adult function, and toward postembryonic mechanisms of regulating skeletal growth, especially ones that respond directly to midlife environments and behaviors.

A tale of two leeches: Toward the understanding of the evolution and development of behavioral neural circuits.

In the animal kingdom, behavioral traits encompass a broad spectrum of biological phenotypes that have critical roles in adaptive evolution, but an EvoDevo approach has not been broadly used to study behavior evolution. Here, we propose that, by integrating two leech model systems, each of which has already attained some success in its respective field, it is possible to take on behavioral traits with an EvoDevo approach. We first identify the developmental changes that may theoretically lead to behavioral evolution and explain why an EvoDevo study of behavior is challenging. Next, we discuss the pros and cons of the two leech model species, Hirudo, a classic model for invertebrate neurobiology, and Helobdella, an emerging model for clitellate developmental biology, as models for behavioral EvoDevo research. Given the limitations of each leech system, neither is particularly strong for behavioral EvoDevo. However, the two leech systems are complementary in their technical accessibilities, and they do exhibit some behavioral similarities and differences. By studying them in parallel and together with additional leech species such as Haementeria, it is possible to explore the different levels of behavioral development and evolution.

A release from developmental bias accelerates morphological diversification in butterfly eyespots

Development can bias the independent evolution of traits sharing ontogenetic pathways, making certain evolutionary changes less likely. The eyespots commonly found on butterfly wings each have concentric rings of differing colors, and these serially repeated pattern elements have been a focus for evo-devo research. In the butterfly family Nymphalidae, eyespots have been shown to function in startling or deflecting predators and to be involved in sexual selection. Previous work on a model species of Mycalesina butterfly, Bicyclus anynana, has provided insights into the developmental control of the size and color composition of individual eyespots. Experimental evolution has also shown that the relative size of a pair of eyespots on the same wing surface is highly flexible, whereas they are resistant to diverging in color composition, presumably due to the underlying shared developmental process. This fixed color composition has been considered as a prime example of developmental bias with significant consequences for wing pattern evolution. Here, we test this proposal by surveying eyespots across the whole subtribe of Mycalesina butterflies and demonstrate that developmental bias shapes evolutionary diversification except in the genus Heteropsis which has gained independent control of eyespot color composition. Experimental manipulations of pupal wings reveal that the bias has been released through a novel regional response of the wing tissue to a conserved patterning signal. Our study demonstrates that development can bias the evolutionary independence of traits, but it also shows how bias can be released through developmental innovations, thus, allowing rapid morphological change, facilitating evolutionary diversification.

In the Spotlight-Established Researcher.

In the Spotlight-Established Researcher.

In the Spotlight-Postdoc.

Masahiro Uesaka is a Guest Co-editor of this special issue on recapitulation. Website: https://www.researchgate.net/profile/Masahiro_Uesaka With whom and where did you study? After I finished my Bachelor of Science in Biology at Kyoto University, I joined Dr. Kiyokazu Agata's laboratory. For my PhD, I studied species-specific long noncoding RNAs and their regulatory roles in epigenetics, working with Drs. Takuya Imamura and Kinichi Nakashima. After completing my PhD at Kyoto University, I moved to the University of Tokyo, where I worked on EvoDevo research as a postdoc with Dr. Naoki Irie. I've continued to work with Naoki even after joining Dr. Shigeru Kuratani's laboratory at RIKEN BDR as a researcher. I was very lucky to have these great mentors, who kindly taught me many of the things important to established scientists. What got you interested in biology? When did you know evodevo was for you? Many biologists say that, as children, they were interested in animals and plants, but I wasn't that kind of child. Until I entered university, I'd never studied biology, but it was at college that I found it to be full of very exciting mysteries. In particular, the diversity and commonality of life fascinated me, so I decided to become a biologist. My research area in graduate school was epigenetics: I studied the epigenetic functions of noncoding RNAs through transcriptome and epigenome analyses. As part of these studies I also read papers and books on EvoDevo topics. That's how I became interested in both evolution and embryogenesis. I found it very exciting to imagine several hundred million years of evolution based on studies of embryogenesis, which occurs in the present day. So I decided to move into the field of EvoDevo. I started addressing the question of whether or not general rules exist between evolution and development. What makes an EvoDevo lab particularly attractive? To address some EvoDevo topics we need to work with nonmodel organisms, so an EvoDevo lab should ideally support the setting-up of a new system to do this. Furthermore, easy access to high-throughput sequencers and sufficient computer resources to analyze large datasets is also important. Fortunately, all the labs where I've worked so far have provided me with such resources and opportunities and have helped me to pursue my own research projects. What is the biggest challenge you face as a young researcher? Young researchers are expected not only to publish papers but also to propose original research ideas and concepts. We have to come up with our own questions that no one has come up with before and try to answer them: This can lead to advances in research. To generate new questions that can change our perception of the world, we need to think from different perspectives. Interdisciplinarity is important for that, because the boundaries between the research fields sometimes prevent us from thinking creatively and freely. I think that not only focusing on one's research topic but also spending more time cultivating interests in a variety of research fields helps us to broaden our perspectives—and that's important for pondering the nature of evolution.

In the Spotlight-Established Researcher.

Tamara Franz-Odendaal holds the NSERC Chair Women in Science and Engineering (Atlantic Canada) and is a Fellow of the American Association of Anatomists Tamara is a Guest Co-Editor of this special issue on Cavefish Website: www.bonedevelopmentlab.ca With whom and where did you study? I completed my undergraduate, MSc and PhD degrees at the University of Cape Town, South Africa. For my MSc degree, I studied gene expression during eye development in chicken embryos under the supervision of Dr. Susan Kidson. My PhD thesis explored paleopathologies and paleodiets of 5 million-year-old fossil herbivores from a South African locality called Langebaanweg. My PhD supervisors were paleontologist Dr. Anusuya Chinsamy-Turan and archaeologist Dr. Julia Lee-Thorpe. Notably, these three supervisors are top female scientists, two of whom had families when I was in their research groups. I completed a short-term DAAD scholarship to pursue a post-doc with Dr. Thomas Kaiser at the University of Greifswald (Germany) and then conducted a 3.5-year post-doc with Dr. Brian Hall (Dalhousie University, Canada), where I got my first true taste of the EvoDevo field. What got you interested in Biology? When did you know EvoDevo was for you? I have been interested in animals and the natural world from a young age. My MSc degree was in developmental biology and I branched out into paleontology for my PhD. Therefore, merging my fascination with embryos and fossils was a natural fit for my post-doc. To have the opportunity to do this with such a remarkable scientist as Dr. Hall was a wonderful experience. If you are amazed at animal diversity then EvoDevo may be for you too since how can you not wonder how that diversity arose both over evolutionary and over developmental time scales. What has been your biggest challenge in getting to your position? My biggest challenge to getting to my position was job searching while having a toddler, being a permanent resident of Canada, and having a degree from a university that was not well known in Canada. I received my first faculty position as an NSERC (Natural Sciences and Engineering Research Council, Canada) University Faculty Award recipient. This program provided me the mechanism for establishing my research program at Mount Saint Vincent University by giving me a reduced teaching load in my first three-years. As an active and productive researcher in Canada, I often have to justify why I chose a primarily undergraduate institution as my home. There are many benefits to teaching at a smaller university such as closer interactions with students and a sense of community. The first time I was exposed to research was during my undergraduate degree and it was an immensely rewarding experience. I view training undergraduates in research methods and analysis as incredibly important since these are the students that become our graduate students and future scientists. Or alternatively, they become our doctors, dentists, and veterinarians; professions that require an understanding of the scientific process. What advice do you have for junior EvoDevo researchers? My advice for graduate students and post-docs interested in EvoDevo is to thoroughly learn as many different techniques as possible, work on different organisms (this will become important if you need to teach EvoDevo or Developmental Biology), and pick your advisors based on how they treat their trainees and their productivity. It is okay (and the norm) to randomly email PI's to ask if they are taking on new students rather than waiting for a graduate position announcement. Do your homework though, and make sure you have read about their research and that you really want to work with them. We established PI's receive numerous applications from students for positions and are very adept at picking out the students who have done some homework about our research. Your first email to us should be to introduce yourself and tell us why your interests or past experiences align with our research group's interests. Always attach your CV or resumé.

In the Spotlight - Established Researcher.

Igor Schneider is an Elected Affiliate Member of the Brazilian National Academy of Sciences and a recipient of a CAPES/Alexander von Humboldt fellowship.Igor is Guest Co-Editor of this special issue on regeneration. With whom and where did you study? I received my PhD degree in Genetics from the University of Iowa, trained by Prof. Dr. Diane Slusarski. My postdoctoral training was at the University of Chicago in the lab of Prof. Dr. Neil Shubin. What got you interested in Biology? When did you know EvoDevo was for you? My interest in biology stems from my upbringing. I was born in the city of Belem, nested within the Brazilian Amazon, and raised by evolutionary biologists; my parents were geneticists and their life work had been dedicated to establishing the phylogeny of new world monkeys. As a PhD student, I was influenced by exciting discoveries in the early 2000s linking developmental processes to morphological change, including work from David Kingsley's lab on pelvic spines of sticklebacks, Cliff Tabin's on beak shapes of Galapagos finches, and Neil Shubin's on Hox genes and the evolution of digits. I have since transitioned from Devo to EvoDevo and never looked back. Which achievement are you most proud of? Establishing a species as a research system is a familiar rite to many in the EvoDevo field. As a postdoc I studied vertebrate genomes, searching for genetic signatures linked to the transition from water to land. I felt then that I needed to study fish species more closely related to land vertebrates than the available research species. As I started my lab in Brazil, I set out to develop lab tools and techniques for research on the South American lungfish, the living sister group to land vertebrates. It took my team 2 years to obtain research and collection permits, and to actually find lungfish in the Marajo island, located a 12-hr-boat ride distance from Belem. A few more years to establish housing protocols, amass transcriptome data, in situ hybridization protocol, to test a plethora of antibodies for immunofluorescence, and so on. We still have a long way to go in establishing breeding protocols and obtaining a genome (lungfish have the largest genome among vertebrates!). Nevertheless, we have begun to publish our findings and thanks the South American lungfish, we now know that salamander-like limb regeneration is a trait inherited from fish ancestors. What are the biggest challenges for EvoDevo researchers in Latin America? The challenges are too many to list. Latin-Americans often and justly stress over how difficult it is to remain competitive while paying more and waiting longer for basic reagents than colleagues in North America and Europe: a set of primers may take 2–3 weeks to arrive, an antibody 60–90 days. In the Amazon, these obstacles compound with lack of basic infrastructure and frequent power outages in universities. However, such difficulties have been part of research in Latin America for decades and many scientists still find ways through creativity, optimism, and sheer perseverance to produce high quality research and training to their students. However, the recent trend of defunding science, particularly in Argentina and Brazil, has revealed itself a challenge too great to overcome. Unless this trend is reversed, we may see many Latin American EvoDevo labs closing and/or researchers moving abroad in the coming years. What do you see as the future of EvoDevo? What drew me to developmental biology in graduate school was the possibility to tinker with development in specific ways to understand how an adult body emerges from a single cell. As a postdoc in an EvoDevo lab I realized the importance of working with a range of lab species to study developmental processes in a comparative manner. Given the breadth of genomes available and molecular tools becoming routine and affordable, I believe that the EvoDevo field will continue to witness a great expansion of novel lab research species. I think this will be essential for EvoDevo; there's so much biodiversity to be explored. If I started anew, I would once again work on establishing a research species to answer questions of how development and the environment shape evolution.

Embryonic and larval development of the northern pike: An emerging fish model system for evo-devo research.

The northern pike, Esox lucius, is one of the largest temperate freshwater apex predators with a characteristic morphology: an elongated body with pelvic, dorsal, and anal fins located at the rear as a functional feature to sprint predation. However, the typical pike character is its head, which is characterized by a long, flattened snout, a well-armed mouth with numerous teeth, and large eyes characteristic of shallow water visual predators. Although the northern pike is becoming increasingly popular as a model system for ecology and evolutionary research, a detailed staging table has not yet been reported. In this study, we report the first comprehensive staging table for the northern pike, spanning from the one-cell stage to the freely-swimming juvenile stage. In addition to classical embryological descriptions, we use a DAPI staining to distinguish individual cells and embryonic structures during the early development. This dataset, in combination with the genomic and transcriptomic resources already available, serves as a foundation for in-depth mechanistic studies dealing with development using this species.