What will result from the interaction between functional and evolutionary biology?

The modern synthesis has been considered to be wrongly called a "synthesis", since it had completely excluded embryology, and many other disciplines. The recent developments of Evo-Devo have been seen as a step in the right direction, as complementing the modern synthesis, and probably leading to a "new synthesis". My argument is that the absence of embryology from the modern synthesis was the visible sign of a more profound lack: the absence of functional biology in the evolutionary synthesis. I will consider the reasons for this absence, as well as the recent transformations which favoured a closer interaction between these two branches of biology. Then I will describe two examples of recent work in which functional and evolutionary questioning were tightly linked. The most significant part of the paper will be devoted to the transformation of evolutionary theory that can be expected from this encounter: a deep transformation, or simply an experimental confirmation of this theory? I will not choose between these two different possibilities, but will discuss some of the difficulties which make the choice problematic.     

The history of scientific endeavors towards understanding hagfish embryology

Due to their curious phylogenetic position and anatomy, hagfishes have attracted the interest of zoologists, especially in the context of vertebrate evolution. Embryological information on these animals is now also needed in the field of evolutionary developmental biology (Evo-Devo), as it is expected to provide hints about the origin of vertebrate traits, whether the hagfishes are an in-or outgroup of vertebrates. This review summarizes the importance of hagfish embryology from a phylogenetic perspective, and the history of attempts to obtain hagfish eggs and embryos. Clearly, the main difficulty associated with these animals is their deep-sea habitat. To circumvent this problem, this review also discusses the future prospects for obtaining embryological material, both from the wild and in the laboratory.     

Evo-Devo: the long and winding road

Evolutionary developmental biology (Evo-Devo) aims to unveil how developmental processes and mechanisms become modified during evolution and how from these changes the past and present biodiversity arose. The first wave of Evo-Devo identified a conserved set of toolkits common to most metazoans. The present second wave has changed gear and aims to identify how genes and modules were used differently through evolution to build the past and present morphological diversity. The burgeoning third wave is introducing experimental testing of predictions drawn from the first and second waves. Here we review some of the hottest topics, contributions and insights of present Evo-Devo related to basic concepts and paradigms of evolutionary research. Future directions of Evo-Devo are also highlighted; in other words, Quo Vadis, Evo-Devo?     

Kowalevsky, comparative evolutionary embryology, and the intellectual lineage of evo-devo

Alexander Kowalevsky was one of the most significant 19th century biologists working at the intersection of evolution and embryology. The reinstatement of the Alexander Kowalevsky Medal by the St. Petersburg Society of Naturalists for outstanding contributions to understanding evolutionary relationships in the animal kingdom, evolutionary developmental biology, and comparative zoology is timely now that Evo-devo has emerged as a major research discipline in contemporary biology. Consideration of the intellectual lineage of comparative evolutionary embryology explicitly forces a reconsideration of some current conceptions of the modern emergence of Evo-devo, which has tended to exist in the shadow of experimental embryology throughout the 20th century, especially with respect to the recent success of developmental biology and developmental genetics. In particular we advocate a sharper distinction between the heritage of problems and the heritage of tools for contemporary Evo-devo. We provide brief overviews of the work of N. J. Berrill and D. T. Anderson to illustrate comparative evolutionary embryology in the 20th century, which provides an appropriate contextualization for a conceptual review of our research on the sea urchin genus Heliocidaris over the past two decades. We conclude that keeping research questions rather than experimental capabilities at the forefront of Evo-devo may be an antidote to any repeat of the stagnation experienced by the first group of evolutionary developmental biologists over one hundred years ago and acknowledges Kowalevsky's legacy in evolutionary embryology.     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科, 它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合, 其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪, 直到20世纪80年代早期, 动物中homeobox基因被发现, 90年代初花发育的 ABC模型被提出, 加之对发育相关基因研究的不断深入, 才使基因型与表型联系了起来, 进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程, 综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状, 讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

植物进化发育生物学的形成与研究进展

植物进化发育生物学是最近十几年来才兴起的一门学科,它是进化发育生物学的主要分支之一。进化发育生物学的产生经历了进化生物学与胚胎学、遗传学和发育生物学的三次大的综合,其历史可追溯到19世纪初冯.贝尔所创立的比较胚胎学。相关研究曾沉寂了近一个世纪,直到20世纪80年代早期,动物中homeobox基因被发现,90年代初花发育的ABC模型被提出,加之对发育相关基因研究的不断深入,才使基因型与表型联系了起来,进而促进了进化发育生物学的飞速发展。目前进化发育生物学已成为21世纪生命科学领域的研究热点之一。本文详细阐述了进化发育生物学产生和发展的历程,综述了最近十几年来植物进化发育生物学的主要研究进展。文中重点介绍了与植物发育密切相关的MADS-box基因在植物各大类群中的研究现状,讨论了植物进化发育生物学领域的研究成果对花被演化、花对称性以及叶的进化等重要问题的启示。     

Embryology and evolution 1920-1960: worlds apart?

During the early part of the 20th century most embryologists were skeptical about the significance of Mendelian genetics to embryological development. A few embryologists began to study the developmental effects of Mendelian genes around 1940. Such work was a necessary step on the path to modern developmental biology. It occurred during the time when the Evolutionary Synthesis was integrating Mendelian and population genetics into a unified evolutionary theory. Why did the first embryological geneticists begin their study at that particular time? One possible explanation is that developmental genetics was a potential avenue of alliance between embryology and evolutionary biology, two fields that had been separated since the 1890s. To assess this possible motive it is necessary to explore the methodological contrasts that obtained between embryology and both Mendelian-chromosomal genetics and neo-Darwinian evolutionary theory. Some of these contrasts persist to the present day.     

Development and Macroevolution: Introduction to the Symposium

Despite the historical relationship between embryology and evolutionarybiology, during most of the 20th century developmental biologyand evolutionary biology have existed as two separate subdisciplinesof biology. Recently a reunion of these subdisciplines beganto take place. This reunion involves the formulation of evolutionaryexplanations of developmental phenomena and the applicationof developmental processes as mechanisms of evolutionary change.The symposium speakers have considered both aspects of the reunionas well as some of the theoretical and methodological issuesthat are emerging from it.     

文昌鱼特异的基因倍增

进化生物学和发育生物学的结合产生了一门新兴学科——进化发育生物学,近年来该领域研究取得了丰硕的成果。头索动物文昌鱼是现存生物中最近似于脊椎动物直接祖先的生物,在与脊椎动物分化后形态改变很小,其基因组未曾经历大规模的基因组倍增,在一定程度上反映了脊椎动物祖先型基因组的特征,但在漫长的独立进化历程中基因组自身还是经历了一些变化。本文介绍了在几例在文昌鱼支系中独立发生的基因倍增事件(Hox; Evx; HNF-3; Calmodulin-like),有力地揭示了文昌鱼虽然与脊椎动物直接祖先极其接近,但其基因组有其自身特性,不能简单地将之等同于脊椎动物直接祖先。Abstract: The union of the two complementary disciplines, developmental biology and evolutionary biology resulted in a new division of evolutionary developmental biology, namely “Evo-Devo”. Recently, the research on this field has been fruitful in understanding the origin and development of vertebrates. The cephalochordate amphioxus, which remains in relatively invariant morphology since the divergence from the vertebrate lineage, is the closest living relative to vertebrates. The vertebrate-like simple body plan and preduplicative genome provide amphioxus genes the privilege to serve as key landmark to understand morphological evolution. However, the amphioxus genome has not escaped evolution. In this paper several examples of independent gene (Hox; Evx; HNF-3 and Calmodulin-like) duplications in the cephalochordate lineage were summarized. These particularities and oddities remind the fact that amphioxus is not an immediate ancestor of the vertebrates but ‘only’ the closest living relative to the ancestor, with a mix of prototypical and amphioxus-specific features in its genome.     

Escaping the mouse trap: the selection of new Evo-Devo model species

Among the many, sometimes contradictory, criteria that have been used for promoting model species, the most prominent has probably been their relevance for understanding human biology. Recently however, the debate has partly shifted from the search for evolutionary conservation (medicine-driven models) to a better understanding of the generative mechanisms underlying biological diversity (Evo-Devo-driven models). Integration of multiple disciplines, beyond developmental genetics and evolutionary molecular genetics, as well as of innovative technologies will help biologists to open the massive realm of living species to genome manipulation and phenotypic investigation. However, a consensual list of model species must still be reached for optimizing the interplay between in silico analyses and in vivo experiments, and we claim that the Evo-Devo community should play a more energetic role in this endeavor. We discuss here a few criteria and limitations of major relevance to the choice of model species for Evo-Devo studies, and promote the use of a pragmatic approach. Finally, given the difficulties related to manipulating and breeding model species, we suggest the development of Evo-Devo virtual zoos maintaining breeding colonies of a selected set of species and from which eggs or staged embryos are available on order.     

Evo-Devo: evolutionary developmental mechanisms

Evolutionary developmental biology (Evo-Devo) as a discipline is concerned, among other things, with discovering and understanding the role of changes in developmental mechanisms in the evolutionary origin of aspects of the phenotype. In a very real sense, Evo-Devo opens the black box between genotype and phenotype, or more properly, phenotypes as multiple life history stages arise in many organisms from a single genotype. Changes in the timing or positioning of an aspect of development in a descendant relative to an ancestor (heterochrony and heterotopy) were two evolutionary developmental mechanisms identified by Ernst Haeckel in the 1870s. Many more have since been identified, in large part because of our enhanced understanding of development and because new mechanisms emerge as development proceeds: the transfer from maternal to zygotic genomic control; cell-to-cell interactions; cell differentiation and cell migration; embryonic inductions; functional interactions at the tissue and organ levels; growth. Within these emergent processes, gene networks and gene cascades (genetic modules) link the genotype with morphogenetic units (cellular modules, namely germ layers, embryonic fields or cellular condensations), while epigenetic processes such as embryonic inductions, tissue interactions and functional integration, link morphogenetic units to the phenotype. Evolutionary developmental mechanisms also include interactions between individuals of the same species, individuals of different species, and species and their biotic and/or abiotic environment. Such interactions link ecological communities. Importantly, there is little to distinguish the causality that underlies these interactions from that which underlies inductive interactions within embryos.     

Modern evolutional developmental biology: Mechanical and molecular genetic or phenotypic approaches?

Heightened interest in the evolutionary problems of developmental biology in the 1980s was due to the success of molecular genetics and disappointment in the synthetic theory of evolution, where the chapters of embryology and developmental biology seem to have been left out. Modern evo-devo, which turned out to be antipodean to the methodology of the synthetic theory of evolution, propagandized in the development of evolutionary problems only the mechanical and molecular genetic approach to the evolution of ontogenesis, based on cellular and intercellular interactions. The phonotypical approach to the evaluation of evolutionary occurrences in ontogenesis, which aids in the joining of the genetic and epigenetic levels of research, the theory of natural selection, the nomogenetic conception, and the problem of the wholeness of the organism in onto- and phylogenesis may be against this. The phenotypic approach to ontogenesis is methodologically the most perspective for evolutionary developmental biology.     

Craniofacial development and the evolution of the vertebrates: the old problems on a new background

Based on recent advances in experimental embryology and molecular genetics, the morphogenetic program for the vertebrate cranium is summarized and several unanswered classical problems are reviewed. In particular, the presence of mesodermal segmentation in the head, the homology of the trabecular cartilage, and the origin of the dermal skull roof are discussed. The discovery of the neural-crest-derived ectomesenchyme and the roles of the homeobox genes have allowed the classical concept of head segmentation unchanged since Goethe to be re-interpreted in terms of developmental mechanisms at the molecular and cellular levels. In the context of evolutionary developmental biology, the importance of generative constraints is stressed as the developmental factor that generates the homologous morphological patterns apparent in various groups of vertebrates. Furthermore, a modern version of the germ-layer theory is defined in terms of the conserved differentiation of cell lineages, which is again questioned from the vantage of evolutionary developmental biology.     

Assessing the prospects for a return of organisms in evolutionary biology

An argument has been raised from various perspectives against the Modern Synthesis (MS) in the past two decades: it has forgotten organisms. Niche construction theorists (Odling-Smee et al. 2003), developmental biologists like West-Eberhard (2003) and Evo-Devo elaborated various views which concur on a rehabilitation of the explanatory role of organisms, formerly neglected by an evolutionary science mostly centered on genes. This paper aims at assessing such criticisms by unraveling the specific arguments they use and evaluating how empirical findings may support them. In the first section, I review the usual critiques about the way MS treats organisms and show that the organisms-concerned critique is multifaceted, and I use the controversy about units of selection in order to show that purely conceptual and empirical arguments have been mixed up when organisms were concerned. In the second section, I consider successively the challenges raised to evolutionary MS by structuralist biologists and then the developmentalist challenge mostly raised by Evo-Devo. I distinguish what is purely conceptual among those criticisms and what mostly relies on recent empirical findings about genome activation, inheritance, and epigenetics. The last section discusses another program in MS, namely "evolutionary transitions" research, as enquiry into the emergence of organisms.     

Developmental anatomy of lampreys

Lampreys are a group of aquatic chordates whose relationships to hagfishes and jawed vertebrates are still debated. Lamprey embryology is of interest to evolutionary biologists because it may shed light on vertebrate origins. For this and other reasons, lamprey embryology has been extensively researched by biologists from a range of disciplines. However, many of the key studies of lamprey comparative embryology are relatively inaccessible to the modern scientist. Therefore, in view of the current resurgence of interest in lamprey evolution and development, we present here a review of lamprey developmental anatomy. We identify several features of early organogenesis, including the origin of the nephric duct, that need to be re-examined with modern techniques. The homologies of several structures are also unclear, including the intriguing subendothelial pads in the heart. We hope that this review will form the basis for future studies into the phylogenetic embryology of this interesting group of animals.     

Boris Balinsky: transition from embryology to developmental biology

This is the story of a textbook that students of developmental biology have used for 45 years. "An Introduction to Embryology" was released soon after a role for genes in the control of development became finally recognized but not yet well documented. Thus this book manifested the transition from embryology to developmental biology. The story of its author, Boris Balinsky, who against all odds survived to write this book, is remarkable on its own. He started his scientific career in the USSR, but due to 20th century social and political upheavals, ended it in South Africa. This article will shed light on the life of Boris Balinsky, a scientist and writer and will explore the origins of his book.     

Life history evolution and comparative developmental biology of echinoderms

Evolutionary biologists studying life history variation have used echinoderms in experimental, laboratory, and field studies of life history evolution. This focus on echinoderms grew originally from the tradition of comparative embryology, in which echinoderms were central. The tools for obtaining and manipulating echinoderm gametes and larvae were taken directly from comparative embryological research. In addition, the comparative embryologists employed a diverse array of echinoderms, not a few model species, and this diversity has led to a broad understanding of the development, function, and evolution of echinoderm larvae. As a result, this branch of life history evolution has deep roots in comparative developmental biology of echinoderms. Here two main aspects of this relationship are reviewed. The first is a broad range of studies of fertilization biology, dispersal, population genetics, functional morphology, and asexual reproduction in which developmental biologists might take a keen interest because of the historical origins of this research in echinoderm comparative embryology. The second is a similarly broad variety of topics in life history research in which evolutionary biologists require techniques or data from developmental biology in order to make progress on understanding patterns of life history variation among echinoderm species and higher taxa. Both sets of topics provide opportunities for interaction and collaboration.     

From development to evolution: the re-establishment of the "Alexander Kowalevsky Medal"

The Saint Petersburg Society of Naturalists has reinstated the Alexander O. Kowalevsky Medal. This article announces the winners of the first medals and briefly reviews the achievements of A.O. Kowalevsky, the Russian comparative embryologist whose studies on amphioxus, tunicates and germ layer homologies pioneered evolutionary embryology and confirmed the evolutionary continuity between invertebrates and vertebrates. In re-establishing this international award, the Society is pleased to recognize both the present awardees and the memory of Kowalevsky, whose work pointed to that we now call evolutionary developmental biology.     

Biodiversity-based development and evolution: the emerging research systems in model and non-model organisms

Science China Life Sciences - Evolutionary developmental biology, or Evo-Devo for short, has become an established field that, broadly speaking, seeks to understand how changes in development drive...     

Haeckel's ABC of evolution and development

One of the central, unresolved controversies in biology concerns the distribution of primitive versus advanced characters at different stages of vertebrate development. This controversy has major implications for evolutionary developmental biology and phylogenetics. Ernst Haeckel addressed the issue with his Biogenetic Law, and his embryo drawings functioned as supporting data. We re-examine Haeckel's work and its significance for modern efforts to develop a rigorous comparative framework for developmental studies. Haeckel's comparative embryology was evolutionary but non-quantitative. It was based on developmental sequences, and treated heterochrony as a sequence change. It is not always clear whether he believed in recapitulation of single characters or entire stages. The Biogenetic Law is supported by several recent studies -- if applied to single characters only. Haeckel's important but overlooked alphabetical analogy of evolution and development is an advance on von Baer. Haeckel recognized the evolutionary diversity in early embryonic stages, in line with modern thinking. He did not necessarily advocate the strict form of recapitulation and terminal addition commonly attributed to him. Haeckel's much-criticized embryo drawings are important as phylogenetic hypotheses, teaching aids, and evidence for evolution. While some criticisms of the drawings are legitimate, others are more tendentious. In opposition to Haeckel and his embryo drawings, Wilhelm His made major advances towards developing a quantitative comparative embryology based on morphometrics. Unfortunately His's work in this area is largely forgotten. Despite his obvious flaws, Haeckel can be seen as the father of a sequence-based phylogenetic embryology.